I was in the same boat and asked the same question. I had just purchased the X two days before the Inc 2 Launched.
The Droid X is nice especially if you download the leaked 2.3 with updated motoblur. Which is what I had done and was struggling with the decision of returning the X or keepin the X.
I decided to return the X and here are my thoughts and reasons why.
1st thing I did was go to Verizon and play with the DInc 2. WOW it feels great in the hand, perfect weight, feels very solid and the sweet spot of a 4" screen.
It is basically the Thunderbolt minus the kickstand, LTE antennae, and has only a 16GB SD card instead of the 32 found in the TB.
Battery life is the best of any HTC phone I have ever owned and in my honest opinion the DInc 2 is currently the best 3G phone for Verizon and the best world phone. Now if you live in a 4G area or will be getting $G in the near future I would check out the Charge. If you are happy with a 3G phone you can not beat the DInc 2!!!