If I had it to do over again I would have done the dame thing (allow the 2.1 OTA to install), having had it now for weeks, and I dare say I was happy with it right from the beginning.
Keep in mind, in most casts, not all but most, if your device is running great with few or no bugs on 1.5 it will do the same on 2.1.
If it's buggy now a likelihood of it remaining buggy on 2.1 has cropped up in the forums; in other words, don't expect 2.1 to fix deep, ongoing problems that you may have in 1.5, it probably won't.