Hello!
I will post this video here which contains the experience of an artist trying krita coming from photoshop.
I post it to try and help you the developers see some bugs or problems with the program that new-users may encounter, you dont have to watch it if you don't want to since it's a really long video but im just trying to be helpful ~

part 1:
https://www.youtube.com/watch?v=3iGE_XpOZVg

part 2:
https://www.youtube.com/watch?v=srQA1QxQ9Qc

In case the videos are too long for you to watch, here is a short summary of some problems the artist raised:
1. Krita's performance in general was too laggy, and he couldn't undo while the post-rendering of the instant preview happened. (a constant theme during those videos, really harmed his experience of the program. do note that he likes to use very large brushes with textures and custom tips)
2. There is a slight freezing when you switch from brush to eraser mode when you have the "eraser switch size" mode enabled. (9:25, the first video)
3. There is no full-screen implemented.(20:27, the first video)
4. The layers are uncomfortable to handle and hard to move (21:30, the first video)
5. Mask layers can't effect anything outside of their group (23:07, the first video)
6. The Liquify tool was too laggy to work with for him. (5:52, second video)
7. The blur filer mask was too slow when you are drawing with it. (13:30, second video)

In general, it seems to me that the performance of the program was the biggest issue this artist faced. despite the performance problems he faced, he still said he thinks krita is amazing, and praised some of the features it has ~

Btw i think he said he uses windows 10 with 16GB of ram (in the comments), a companion 2 tablet, and a "kind of a weak Intel graphics card"
I hope you find this input helpful!

Hey,

One of our developers, Scott, actually already answered the reviewer on youtube, so we're not unaware of the issues. For instance, full-screen had to be disabled for Krita 3.0 because of a bug in Qt. For 3.0.1, we've found a workaround. Some things are known, some things are already fixed, some things, like Mask layers (what are that? layers or masks -- it's not the same thing) could be because groups in Krita are handled differently. But there is nothing really new for us in this list.

If you want to be helpful, check bugs.kde.org, search for krita and check all unconfirmed bugs and see whether you can reproduce the issue.