I've never found TR to be "[i]clunky and slow[/i]."
Temperamental SURE - but neither clunky nor slow.
Most of the other forum engines that I've seen might appear faster but navigating around them is pitiful, and maintaining [u]who said what (and when)[/u] and [u]who's replying to which previous post[/u] is simply a nightmare. I simply cannot abide the forum engines that HAVE TO quote the previous relevant post, just so's you can keep track of what's happening.
Then there's the utter numpties that populate these sites. That is where a site falls down - not whether it's faster or slower. ;)
Typo.