I wouldn't rush straight to choosing Iowa. Though I may be biased because I've chosen UNLV I think there are some advantages/disadvantages to compare. Here's a good comparison list:
Facilities: Iowa (OLD), UNLV (really new)
Weather: Iowa (snow), UNLV (heat)
Tuition: No big difference
Cirriculum: Iowa (textbooks), UNLV (laptop)
Location: Iowa (???), UNLV (in Vegas obviously + a couple hours to CA)
So yeah, I'm a little biased but UNLV seems like it would be a lot more exciting for ya to me. Chose the one that you felt the most comfortable at. If UNLV still seems a bit out of sorts because of their newness then definitely go to the tried and true Iowa. Good luck!
BTW, when did you interview at UNLV? You from CA? I thought there was somebody from my interview group who was accepted at Iowa.