When Mountainside was founded, the motto was "the friendliest gyms in town" and they definitely are! The staff at this location are always so friendly. I'm always promptly greeted by a staff member with a smile and great attitude. I've been to many gyms where the people checking you don't say a word to you and often times put the scanner on the counter as to have customers check themselves in. I've never seen this at any of the Mountainside Fitness locations and not that the others don't have great staff, but I definitely think this location has the friendliest staff of them all.
The parking lot fills up during the mid morning rush (when they have classes... 9-11) and that's the busiest I've seen it with people parking along the entrance road so be prepared if going to any of those classes. Like any other gym, during the hours that they have more classes and after work hours are going to be the busiest.
I can only speak for the yoga classes, as I haven't taken any others, but they are amazing. The Flow and Power classes are both challenging (some instructors a bit more than others) so be prepared to sweat.