The one X is great, I personally can't fault it. It seems really efficient with the battery too. I regularly only use 50 to 60 % in my 16 hour day. Which includes listening to music, checking for notifications every 15 mins ( neurotic I know) playing temple run on my region journeys etc.
The screen is amazing, I looked at my old Desire the other day and I couldn't get over how antiquated it looked! It is lighter as well. The phone also takes really great pictures imo.
The phone can get a little hot when playing the tegra optimised games. It also seems to find less signal strength than my desire did, with it receiving "h" often in places my desire found 3g.
Hope that helps!