Meadows is a lot nicer in my opinion
I've been to both several times. We enjoy both, and both have their slight nuances (they're slight, which is why I think you'll like each equally.
Meadows is quite a bit bigger, thus a bit more traffic (obviously only relevant during crowded times). However, they have more pools, outdoor things like shuffle board and ping pong, a movie theater inside the rec center. In the winter, their indoor pool has been much warmer than Mountain Vista (MV). So much so that this last NYE, we stayed at MV but used the Meadows' pool.
One thing that is remarkable about the kitchens...MV actually has pantry/shelf space in the kitchen; Meadows is a struggle for that. But we're a family of 5 and have a lot more food that a couple wood, so take that as needed.