SIMDUDE  Excellent review and comparison. I too use and like both but for more tasks, prefer BBedit. For me the reason is simply performance. At work, my company has mostly eliminated macs so I'm still using my old dual 450MHz G4 tower. Old, but still capable. That is unless I use Textmate to open a big file. Searching is pathetic and multiline editing so slow it's unbearable. I've been learning Ruby and for that, the bundles are great.

I think a good comparison would be to do some timings. Opening and searching a larger (>10MEG) file, doing large column selections etc. Granted, many users may only edit small files and this stuff isn't important. But the performance of TextMate has kept me from using it as a primary editor. As I understand it, the next version will be Leopard only, so that really kills it for slower machines (Leopard needs ~900 MHz G4).  
(Version 8.7)