If you are buying a tablet PRIMARILY FOR GAMING, get an iPad. If you are buying a tablet for tabletty purposes, and want to be able to play games on it, then whatevs. There's no question that the iPad has way more games than Android, but it's also the case that Android has lots of games -- anyone who's interested will find scores of games to entertain them.
As for phone games not working on tablets, in my experience the only ones that don't work on tablets are ones that don't work on modern phones, too -- the ones that freak out at high DPI and high-res screens. For the most part, they're fine.