So.. I cant decide what i should use, OpenSUSE or Kubuntu. And i mean in speed etc.. OpenSUSE will be the KDE4 version. Which you recommend, if i have those specs:
CPU: AMD Athlon II X2 2.1 GHz
GPU: ATI Mobility Radeon HD 4250 256 MB
RAM: DDR3 2GB

if you're running K now and are familiar and happy with it why change? there will be differences, none great but if it's working for you why change.

here's a couple pluses on each
openSuse
- Yast, centralized system tool more complete than what K provides
- there are more current packages for older versions
- there's a pseudo rolling release version (Tumbleweed)

Kubuntu
- there's a couple of packages not available elsewhere like Boxee
- the software center (though I understand the U version is nicer)
- 6 month release cycle (vrs 8 month)

Well someones said OpenSUSE runs KDE better and faster, so i decided to ask does it actually run better with HD 4250 graphics card.

I've never used openSuse, so I will summarize Kubuntu.
Pluses:
-Huge sofware repository, kept in sync with Debian patches (I think they still do this)
-Easy maintenance
-LTS version for users who prefer stability and "system which just works"
-Latest KDE available during release time
-Sane release schedule
-Popularity
Minuses:
-Annoying bugs
-Quality of new releases
-Alot of newbies posting possibly harmful howtos on forums/wikis
And at the end, some people love this, personally I think it's asking for troubles: Personal Package Archives

My personal favorites are openSUSE(most polished desktop of any kind) and Arch(rolling and slim). But if one is already bit familiar with the underlying system, Kubuntu is good enough desktop to stay with it. I put Kubu on few friends machines because of the Software Center, so they won't constantly ask me where/how to get some programs