Been running 1.3 for a few weeks now without any problems. It does seem to impact battery life overall, so I've kept it going. If it gains me 1 hour a day on the Touch Pro's already short battery life, I'm all about it.
Only thing I've noticed that's wierd (and I'm assuming has to do with the cut down clock speeds) is that when I'm at my sisters house (she's on the edge of Sprints coverage) it kicks into roaming a lot when it's suspended and kicks the backlight on. My sister's touch pro did this constantly with the underclocking turned on. Now that it's off she doesn't have the issue.