Avoid at all costs. The DX with GB is a POS. Expect to reboot twice a day, lose all connectivity randomly, lose GPS, etc. Just check the GB post.
Been running GB on my DX since a bit before official release and have not had a bad experience. I do get random reboots from time to time (maybe 1 every 7th day or so) and have had the connectivity loss once. I wouldn't call that a deal breaker. Minor annoyances, yes.
My DX runs perfectly on the OTA Gingerbread. Not one reboot or issue of any kind since installing it. I suspect that it's more of a software conflict than a DX or a GB issue. I think it could even be a conflict with moto blur (I use Launcher Pro). Anyway...the DX is a great phone. Having said that, if this is a money issue (sounds like it is from your OP), and you're resorting to buying used devices off of Craigslist, I'd hold off. If you're not satisfied with your facinate, I doubt the DX will change your world. Wait for your next update time and get a duel core 4G phone. If you've got money to blow, go for it.
I've had my DX for about 3 months now. Running GB, rooted, odexed. I have had virtually 0 problems with GB or before that with Froyo. The few problems I have had I've been able to trace to applications (i.e remove the app and the problem goes away). I wish that before people speak about something being a major problem, that they give some context. What are you running, overclocked, major apps,..., If the DX were as bad as some people here seem to say, none of us would be here. I think generalities do not help any conversation, could mislead people, and are of no real value.