I say it depends on what you want to do with the device. Also I say look at the ecosystem. Hands down that is apple & kindle fire. Then you look at size. If you'll be wanting to do some productivity, thn you'll want to go with the iPad. If you'll just be playing games, music, movies, email, reading, then the kindle fire. I don't know much about the xoom other than it had some hardware issues. Someone else will hav to jump in on that. Also the new Xoom 2 was announced, the Xyboard. So that may be a consideration, they are going to be quite a bit more than an iPad & have a 2 yr contract. Maybe the transformer Optimus prime fom asus would be one to look at also, or the acer iconia.
I have the fire & the iPad. They both are very good devices. I would just think about your specific use case & also some longevity. Some of these companies are not too quick to update or they update hardware as fast you are left in the digital dust....& you don't want bytes in your eye.
Good luck. Let us know what you decided.