Im on my second go round with Tayutama's ROM with the setiron kernel. I have had no problems at all, and all told, I've probably logged a week with this set up.
I have also used 5 or 6 different Cognition Betas with no major problems.
I wonder if you are doing something that is causing your problems, or if it is your hardware. Seems odd that certain phones are ok with the froyo Roms, but others aren't. Although I wouldn't be surprised if samsung has tweaked the phone to make it less developer friendly for at&t.