I just went for the X after having the Skyrocket for 3 months. Before that phone I had the Atrix. The Skyrocket was fantastic compared to the Atrix, but the X blows away the Skyrocket.
The phones side by side are pretty much exactly the same size, except the screen on the X goes amost literally from edge to edge. So anyone complaining that this phone is too big, clearly isnt holding it right.
I was using several launchers on the SR(abbreviating Skyrocket) and they were good but using up valuable battery and somewhat slowing things down. The Sense on the X is almost exactly the way I would set up the phone with a launcher so now I dont need anything else overlayed, its that good(for me at least).
I dont know if its ICS exactly but the application transitions, options and just overall usefullness of the phone makes doing everything faster on the X. Sound quality from the external speaker is very loud and clear, substantially so from the SR. Sound quality on the internal speaker is just as good as the SR with no complaints from the other end.
First fear I had when switching phones was, how am I going to get everything from my SD card over to the X. It was just as easy as making a folder on my desktop and pulling everything off the SD card and then dragging it into the respective folders on the X. I dont know why people are complaining about storage space, there is TONS available. Then again, Im not downloading songs or movies on to my phone.
One thing Ive seen is the antenna strength seems to be one bar less than I was with the SR in places that I know. I havent dropped signal yet so thats a good thing but Im wondering how the antenna placement in the polycarbonate shell will perform in the long run.
For the first time, I feel I have a phone that nothing else on the horizon could pry my hands away from.