I'm a 5+ years happy user of KDE3 through a number of different Linux distros.
Being KUbuntu the last one running a rather stable KDE 3.5.10.
Now I'm considering to jump on the KDE4 train but have no idea what I'll be missing.
I skipped the v4.0 "release" as it was clearly incomplete.
The next KUbuntu release (due in a couple of weeks) will have the v4, hopefully the v4.1.2 (or newer).
Is there anyone that knows which components are not yet implemented into the current KDE4?
And, more important, is there any "comparison chart" or "vesrtion-feature grid" for a comparison?

Thanks a lot in advance for any help.

I believe this article will be of help: http://techbase.kde.org/Schedules/Is_KDE_4.1_for_you%3F

K3b, Konversation, Stable Amarok, Stable Koffice.
those are the things that I miss the most, but amarok is in usable beta. don't know for koffice.

As long as there is no stable KDE 4 equivalent, the KDE 3 versions of this applications are still available.

JontheEchinda wrote:http://techbase.kde.org/Schedules/Is_KDE_4.1_for_you%3F

It's and interesting page that would deserve a sticky place somewhere.
Hmm ... I don't see features/programs like:
KBluetooth
kwalletmanager
knetworkmanager
and the modules of the systemsettings container

Any info about them?
Thanks so far, though.

There is a KBluetooth for KDE4, though at the moment it's a bit broken in Intrepid due to an API change. The bluetooth guys are working on fixing it though. There is a KDE4 version of KWalletManager. KNetworkManager is still at it's KDE3 version in Intrepid.

- more crash-resistant desktop (in KDE3, crash caused by SuperKaramba widget could at most crash the widget layer; in KDE4 a single widget problems can render the whole desktop unusable, including the panel with K menu and icons on the desktop); I had many problems with widgets in the past, so I am skeptical regarding the new solution
- Baghira style
- stable Krusader (I don't know whether there will be a KDE4 version or not), stable Digikam, KRename
- some other apps, like Twinkle or Noatun (I still do use it sometimes, despite I have Amarok installed)
- panel clock functionality, that displayed time in several (user defined) timezones, after mouse pointer was left on the clock for a short moment (really nice feature for someone contacting with people from all over the world)
- classic K menu (the KDE 4 classic menu cannot display last sed applications); I have tried to use the Kickoff several times, but eventually I was always returning to the classic menu
- stable Gadu-Gadu IM protocol support in Kopete - latest KDE 3 versions and KDE 4 have problems with it; at least I can see some improvements with 4.1.2

And probably several others...

Romanujan wrote:- more crash-resistant desktop (in KDE3, crash caused by SuperKaramba widget could at most crash the widget layer; in KDE4 a single widget problems can render the whole desktop unusable, including the panel with K menu and icons on the desktop); I had many problems with widgets in the past, so I am skeptical regarding the new solution
...

All these feedbacks sound scaring!
I have read a lot about the controversial 4.0 release back in January and it looks like I'll wait for a stable-to-stable later jump (unless those issues are related to (k)ubuntu only).

Is there any web page showing the "maturity" status of all the KDE components?
As far as I understand, the applications themselves should work fine with both KDE3 and KDE4.
I'm more scared by the core components and by those bits that work very closely on my desktop (the ones I mentioned earlier).

Don't worry. Despite the increased susceptibility to crashes caused by plugins the KDE 4.1 desktop really is stable. Since the upgrade to 4.1 I've really only had 1 crash doing normal everyday things.

I am a GNOME user primarily and there are still little window manager things missing that I use on a daily basis with metacity or compiz. I found that a number of the plasmoids were kind of broken as well. So I decided I would wait for 4.2 before attempting to use it again. Although I enjoyed the experience overall and will likely switch to KDE 4 at a later release.

[EDIT]
I am using ArchLinux by the way.

JontheEchinda wrote:Don't worry. Despite the increased susceptibility to crashes caused by plugins the KDE 4.1 desktop really is stable. Since the upgrade to 4.1 I've really only had 1 crash doing normal everyday things.

Good to know.
I run production PCs that rely on things like KBluetooth and knetworkmanager and so
I'd like to keep an eye on a kind of "advancement status page" for them in order to know when it makes sense to test the new KDE version.
Occasional crashes (well, not too wide of course) can be OK also to help developers with feedbacks. But missing or unstable applications can kill my production environment.

Thanks again so far.

For me Kubuntu 8.10 is already stable, but what I'm missing is KDE 4 application like K3B,Koffice,digiKam,Amarok. I know there are beta's alpha's but still you have the felling you missing somethings/feature's.

Romanujan wrote:- more crash-resistant desktop (in KDE3, crash caused by SuperKaramba widget could at most crash the widget layer; in KDE4 a single widget problems can render the whole desktop unusable, including the panel with K menu and icons on the desktop); I had many problems with widgets in the past, so I am skeptical regarding the new solution

I had that problem a few (okay, more than a few...) during the 4.0.x series but I have yet to encounter it when using 4.1.0 or later. I'm not saying it's gone (one installation is not enough to judge that by), I am only saying that I think the chance of it happening has decreased a lot.

Romanujan wrote:- Baghira style

Only a problem if you want KDE to look like MacOS X. Personally, I don't. MacOS X is ugly in my opinion and if I wanted MacOS X I would have gotten a Mac. Still, no accounting for taste...

Romanujan wrote:- stable Krusader (I don't know whether there will be a KDE4 version or not), stable Digikam, KRename

Krusader and Digikam for KDE4 works fine IMO.

Romanujan wrote:- some other apps, like Twinkle or Noatun (I still do use it sometimes, despite I have Amarok installed)

The KDE3 versions, when a KDE4 port is not available/stable enough yet works fine if that should be a problem for the user. I do that for Amarok for example. No, the KDE4 version of Amarok is still too crash-prone for my liking. But yeah, that's my main gripe with KDE4 at this time.

Romanujan wrote:- panel clock functionality, that displayed time in several (user defined) timezones, after mouse pointer was left on the clock for a short moment (really nice feature for someone contacting with people from all over the world)

Is supposedly there in 4.1.2. I say supposedly because I am not sure if I did something wrong or what, but I can't get the damn clock to show the three timezones I'm interested in.

Romanujan wrote:- classic K menu (the KDE 4 classic menu cannot display last sed applications); I have tried to use the Kickoff several times, but eventually I was always returning to the classic menu

I'm not sure what's up with this. If you have the classic menu as default (as it is in KDE 4.1.2.) it does not show the last used applications as you say. However, if you right-click on it in the panel and choose "Application launhcer settings" you can set it to show only the recently used applications and/or documents. I agree that's a regression from how it used to work in KDE3 where you could get access to everything from one point-of-entry. Well, regression depending on how you use it I guess. Personally, I've switched to Lancelot (I never was a fan of Kickoff either). But before I did that, I used two K-menus. One for applications and one for recently used items. It sounds more awkward than it really is - at least it was for me. It took a little while to get used to but it works surprisingly well (okay, it's a workaround but one that worked for me. If you don't like neither Kickoff or Lancelot, it may be worth a try. Or Launchy).

Just my two cents...that are increasingly decreasing in value

stable Krusader (I don't know whether there will be a KDE4 version or not)

Krusader2 from ubuntu PPA is pretty stable for me.

As regarding Krusader and Digikam - I prefer to wait till developers call them stable. If I have some time I may install them, try to crash them, send some feedback - but I do not use beta software for daily purposes, unless I have a really good reason to do so.

As regarding the desktop crashes - well, I have never really experienced them with KDE 4 but I could observe Plasma freezing or going unusably slow (the crashes I was talking about were related to SuperKaramba in KDE 3), so I will remain skeptical for now.

Regarding Baghira - well, I like it, so I will be missing it. Matter of taste

Running KDE 3 applications in KDE 4 environment is like running Gnome apps in KDE or vice-versa. I does work, but you don't have this wonderful integration and style consistency (it's even better with Gnome, there is GTK style that uses Qt style for rendering; other possibility is to use a style that have versions for all environments, but there is very few of them...). Again, I would need a really good reason to do so.

Right now I cannot see any reason for me to switch to KDE 4 - simply put, too many good old features and apps are missing (there are more things I miss, like the printing subsystem - I just didn't repeat things mentioned by someone else). I will certainly wait for at least 4.2 before I decide to switch. Perhaps even to 4.3.