Good job, I think, it went better than expected.
Here are some benefits I noticed right away: Being able to disable signatures is awesome, and a definite advantage. The loading speed is not slow either, I think maybe 10% slower but still pretty fast. Quoting looks like it is very efficient. The Topic Summary is cool. Being able to put newer messages first is great. The Preview button works nice.
I do think some issues could be solved with a new theme, but I don't know enough about board themes to make one. The page headers everywhere take up a lot of space. It's odd, because they did on the old forum too, but it didn't bother me for some reason. I'd like a theme that is more compact, so you can see more topics on a page. The pointless "Logged" icon is wasting space in each message. A lot of places have unnecessary margins.
Oh, my biggest issue now is the Search. I'd like to search for all posts by a user in the last 15 days, but Search requires a keyword. And you can't use "the" or "a", or search for all posts without asparagus. I tried searching for Dwarf, but it seemed like there should be more. It was slower than the old search, and the results were bloated. I just need a list of topics and post #, like before.