I'm not sure if its only me or anyone else facing the slowness while editing and quick replying the post.
I don't think I've particularly noticed anything and what I have noticed is probably my internet :p
It seems to be faster for me. Without Subversion, Wordpress, and Wikimedia (Plus the addition of CloudFlare) we have less of a load on the server so it's most likely an issue with your internet.
It's loading instantly for me. I haven't seen any slowness at all.
It's been a lot faster for me since the server move for sure.
Strange, it may be your location. If MyBB's host is on the other side of the world to you, the signal has to be processed by quite a few ISPs.
It's been a bit slower for me lately, but not taking approx. 45 seconds to show the result.
Fast enough for me in Europe on Dial up, the link took 6 seconds.