On 2.1 my Droid X was rock solid (months of uptime - no crashes or anything), however under 2.2 its been frustratingly flakey.
Yesterday before going for a jog I trying to queue up some music, but the phone slowed down to a crawl, the music app wasn't functioning and when I went to go kill it - the entire phone hanged - this behavior has happened several times. Sometimes if I wait like 5-10 minutes the problem just magically goes away.
More than once when it detects a wifi hub (like at work or home) that I have access to it leaves the 3G radio on - the phone gets surprisingly hot.
I was so excited to download 2.2 yesterday. After the download and update my X started randomly freezing, showing delayed reaction to my touch and several complete lockups. I tried several battery pulls and restarts to no avail. All yesterday afternoon and this morning it was impossible to use and it drained battery like no tomorrow. I was ready to throw the phone against a wall (I just past my 30 days for returning it). I checked the battery usage and noticed that the largest use of the battery was going to gmail. I immediately uninstalled the gmail update through the marketplace and now all is good now.