I don't know what it is about Mexican cantina-style places in AZ that gets people so excited. They're basically outdoor stand-around places with free corn chips.
Yea, Salty's has a nice outdoor patio with tables and heaters during the winter time, but I go to Mexican restaurants for the food.
The food here is decent. Servers will make the guacamole for you right at your table and I enjoyed their carne asada burrito. This place is overpriced though. Can't speak for the Mesa location, but I think you pay for atmosphere...or the location.
Parking here is also pretty poor as it's located in the heart of Old Town Scottsdale. I've been here on a Thursday night and Sunday night and thought it was far more comfortable to spend time there than on weekends.
Salty has a busy happy hour crowd. I don't recommend going for dinner on a weekend night because it's just too packed. Plus, as I mentioned, food is a bit pricey.