I can't really say much about SGU, but KCOM is very well-established, and they are one of the heavy-hitters in the world of medicine. They know exactly what they are doing, and have been doing it the right way for a long time.
I don't understand why anyone would go to another country to become an American doctor unless they had absolutely no other choice. On the other hand, if you wanted to practice in central america or Mexico, SGU would probably be a great choice. But between KCOM and SGU, I think you know a little more what you're getting with KCOM.