The missus has had the one x for about a month now, she upgraded from the desire too. She's really pleased with it although i can't see its that much different from my Galaxy SII (which is a compliment because I love my phone), especially as they both run Android's Ice Cream Sandwich OS.
The screen on the one x is slightly bigger than my galaxy (which may or may not be a good thing, personally, I don't think i'd want my phone to be any bigger than it is now) and the battery power seems to last quite well on the one x. She certainly hasn't grumbled much about it in the first month...