I haven't noticed much of a difference in speed. There have been days when it was slow, but everything else was too, so I blame it on my ISP or Internet traffic in general.
Then again, I'm still using dial-up so "slow" is a very relative term to me.

I have had some other weird things happen. I sometimes get a window asking me if I want to save/open/or cancel a file when posting. I just cancel and I get sent back to the Phorum sub section instead of into the thread, but the post will get added.
Another strange happening is with the spell check function. It turns parts of the page into "mouse-overs" and will turn the spell check off. But again this is only once in a while and not every time.