If the UI turned you off before, you probably won't be very happy with the game as it stands, regardless of the bugfixes - of which there haven't been many in the past six months; I think Aaron has basically given up on supporting SE5
Yes, PBW does work with SE5, but later in the game the turns do tend to time out so you'll have to run them manually at some point.
I wouldn't say the community is moribund, but it's not as strong as the SE4 community was at the equivalent point in SE4's lifecycle... there is however a PBC (Play By Committee) game starting up in SE5!
http://z10.invisionfree.com/PBC_SEV/index.php?