I like it best spelt Maya. I say MY-a for both, but I like MAY-a too, (although I wouldn't get that prn from Maia, it only makes sense with Maya and Maja, IMO).
This is one of those names that I quite like, but tend to forget about. There's a character called Maia on a show I watch who I don't like most of the time, so I tend to go off the name every now and then lol. It's also quite popular in NZ at the moment (don't know about where you are) which sort of puts me off it a little.