I think it mainly comes down to whether you want a keyboard or not - back when there was only the Moto Droid and Droid Eris to choose from, I went with the Eris because I thought the Moto Droid's keyboard sucked, and since it's a slider you can't put a rubber cover on it. If the Incredible had been available at that time, I probably would have gotten it, but instead I got the Eris, which I am pretty happy with. I think HTC makes a good phone, and their Sense UI makes Android slicker and more fun to use.
I believe also that the Incredible has somewhat better technical specs than the Moto Droid too (faster maybe, more RAM maybe, better camera maybe, etc...)
I believe also that the Incredible has somewhat better technical specs than the Moto Droid too (faster maybe, more RAM maybe, better camera maybe, etc...)