I've been a member of this gym for a year to date and going during my lunch hour downtown has changed my life. All of the exercise equipment is state of the art and has its own monitor for watching Law and Order while your run a quick 5K at lunch. Or you can take one of their many lunch hour classes, and I've tried all of them. All of the instructors are passionate and caring, from butts n' guts and spinning to yoga and Pilates, and they are all included with the $50/month membership, which is a really great deal.
Downsides: the women's locker room is way too small, you are always bumping into someone while you change, but for the most part everyone is very considerate and friendly so it's not that big of a deal. Also, because the classes are so great, you have to call in the morning to sign up and you won't always get a spot because I swear some people must be calling at 5am.
Overall, a really solid place to work out if you work downtown and have a decent lunch hour.