I saw the X in the store as well and mine will be arriving at my house hopefully tomorrow. The X seems so much faster in just using the phone, opening and closing apps, etc., nice, no delay like my current Droid. I love my Droid 1 but the delays seem to be getting more annoying lately, delays I never noticed before checking out the X. (And BTW, I am over clocked to 800MHz and rooted) I love the screen, I just seems really big compared to my D1, I hope it fits in my pocket.
I was deciding between the Incredible and the X and I like the "vanilla" operating system of the X as compared to the Incredible's Sense UI. Besides, the car dock and desktop dock helped me make my decision FOR the X as well. The X seems very solid and the battery is rated longer than the Incredible's. I also like the dedicated button for the camera and I like the physical buttons on the bottom, home, return, back and menu. I always had issues finding the correct "spot" on my current Droid for the home key for some reason. Oh, not to mention the HDMI out is pretty sweet, can't wait to try that.
The only complaint about the X that I saw in the store (still running 2.1) was the app drawer. When I opened it it didn't seem as silky smooth as say, the Samsung Vibrant, which was VERY smooth and had a nice screen as well.
Anyway, to answer your question, YES, the X is worth upgrading to from the D1. Just my opinion.