Frankly, I am extremely pleased with this latest update. My phone is far smoother, quicker, and the random reboots I was experiencing are gone completely.
A lot of people are dismissing this update as minor and not worth it. There's some validity to that if you are experiencing zero problems, but I am a very happy 2.2.1 user and think it was a very worthy update.
Also, "waiting for Gingerbread" really isn't a good way to approach this since we have no idea when or if Gingerbread will be pushed to the Droid X. Given the timelines involved, there's a good chance we'll get it - but that shouldn't be taken into account here. Either you're very happy with 2.2 and have no problems at all, or you should update to 2.2.1. Frankly, I had very few problems before, but I have even fewer problems now, so I say go for it.