I thought I'd share my experience with ACE ROM, good and bad, for those who are experiencing freezes and other bad behavior.
I bought my Epic the day of release, and never had to pull my battery due to a lockup once while running Eclair and then ACE ROM 1.7, which I installed not long after Paul released it. In fact, I was dreading ever having to take my "Fort Knox" case off the phone to remove the battery, as it looked pretty formidable (fortunately, it wasn't bad at all).
I upgraded to ACE ROM 2.0 shortly after Paul released it, figuring it would even better than 1.7, which I was very pleased with. Not long after, I got my first bad lockup that forced a battery removal, and it's been about a daily occurance since then :-(. Camera photos are often the culprit, and I would say about half the time when I would attempt to power down the phone, it would freeze, forcing another battery removal. Rather annoying and unexpected, especially after the smooth ride with 1.7.
Last night I'd decided I'd had enough. First thing I did was buy SetCPU through the Market, and I set the minimum and maximum values to 200 MHz and 1000 MHz. The phone promptly froze on shutdown, out came the battery. After powering back on, I set the upper value to 800 MHz, which seemed to help. I didn't create any Profiles in SetCPU, and I checked "Set on Boot" so it would retain those values on power down/up.
I then flashed the Vision 1.1 kernel, replacing the default ACE ROM 2.0 Twilight Zone 1.1.1 kernel. Yes, you must be rooted and have ClockWork installed along with the other goodies to do this, plenty of instructions at the front of this thread on that.
It's only been a day, but I haven't experienced a freeze since installing these 2 items. I have powered down my phone at least a half dozen times, and no lockups

. As Paul had mentioned several times previously, kernels are often the source of freezing and erratic behavior and that appears to be good info, at least for me. It appears when it comes to kernels and the Epic, one size does not fit all.
I'll check back in a few weeks with an update, hopefully my Epic continues to avoid stop motion. Thanks Paul!