The lack of awesome hardware like the Moto Droid was the deal breaker for me. The lower cost is awesome, but it's basically the same as the other Android phones that have been on the market. Sense UI is awesome and I wish it was on my Moto Droid, however I am able to get out of Open Home a good amount of flair (home replacement app).
The hardware capabilities and Android 2 had me sold, couldn't tell myself to save money by abandoning those features. Well worth it too, the integration of information for contacts is absolutely amazing.