I have the Incredible and just picked up the Droid X this morning. I haven't really had a chance to do much with it yet, because I'm busier than usual today.
I agree with Scott on the widgets. I came into Android with HTC Sense, so I got a little spoiled, I think. So far, the widgets on the Droid X are decently, but not quite as elegant as they are on the Incredible. Additionally, I noticed that HTC allows you to add program icons onto a screen by using the long hold. With the Droid X, you have to go to the app launcher, find the program, and then long hold. It's not that big of a deal, but far more convenient to add programs with Sense UI. I do, however, like that you can move widgets from one screen to another by holding and moving left or right. Additionally, I like that I can resize widgets. Sense has varying sizes for some widgets, but it seems like all of Motorola's widgets can be resized. Oh, I also like that I can add multiple one-touch functions on the people widgets. HTC Sense makes you choose one default function.
I've found the browser speed to be about the same as the Incredible. Same goes for the responsiveness of pinch and zoom.
I can say, without out a doubt, that this larger-finger, having user loves the Droid X's keyboard (both orientations). When I was in the store setting up the phone, I was immediately wowed by the ease of typing.
My son is getting the Incredible, but I plan to add some comparison notes in my first impressions piece on my blog.