I used a 3-month trial membership purchased from Costco. Great way to try it out without the contracts & usual commitments. I was pretty excited about this gym because of the class schedule. Well the week after I joined, they started their "summer schedule" which removed a number of the classes I had specifically joined for. The evening schedule didn't offer much past 5:30PM which didn't work for me.
The place is very nice, including the locker area. Morning desk staff were always very pleasant and welcoming. Fresh towels always available. Class instructors vary, a few were very good and some were not very inspiring.
One thing I noticed is that they really hype the additional fee classes. They offered a host of these thru the summer while they cut back "the included in the regular membership" classes. So they can tell you they offer lots of classes, but you need to know you also get to pay EXTRA for them. Good deal - for them.
When my 3 months was up, I decided to go back to 24Hr Fitness (also thru Costco). The extra cost at Mountainside just didn't add up for what they offered.