If frequent updates are your thing I'd suggest looking at roms made by someone who actually uses the device and therefore has a vested interest in maintaining the rom. That's what I'm starting to do. As of this moment I see three roms that have been updated in the past three days:
[3-17-09] grooveROM 4 WM 6.1 & 6.5 versions [Rhodium Manila, HD Manila & Manila free]
[03-17-2009] Juicy ROM 4.6 by JMZ (CE OS 5.2.21028 Build 2102
[March-15-09] Mystery's v1.4 [All Carriers] (CE OS 5.2.21028 Build 2102
Anyone try any of these out? How do they compare (stability/features/bugs) to MightyROM 4.6?