I have latest Kloxo-MR running on 2 Centos-7 VPSs, and it has in general been working quite well the last year although I am a complete newbie. Most of my issues I have found answer to in the forum. Even webmail that I read many had issues with, has worked ok for me. However, I have not got the cache systems to work with my setup, so my VPSs are running without active cache, but still speed is ok.
I have donated a couple of times and also asked questions, but as you know MR has not been active in the forum since september last year, - so my issues are still open. One of them is the THT script which is not working.
I have resently considered to switch to another CP, but if Kloxo-NG is progressing I will stick to it as I have spent so much time to learn to use it, and I like it.