I'd say keep the walmart bike for random less than great conditions. They aren't great bikes (most are pretty far from good) but they usually manage to get the job done. I own one that I use to ride to campus with. I hate it and its not fun to ride but nobody wants to steal it and I don't care if idiots ram it up against the racks while I'm not looking. Sounds like the schwinn is a pretty sweet deal though. Nice hunting, enjoy it!