I signed up for 1-2-1 because I can get it free through my health insurance at work. I have several friends who go there as well, and they seemed to like it. I was also completely tired of exercising at Bally's in Severance due to the unusually high numbers of creepers there.
I'm pretty impressed, actually. It's small, it's a little crowded, but most people seem to mind their own business and get their work out in. The interior is a little drab, but I'd prefer this over bright colors. The equipment is well maintained, I rarely have to wait for a machine, and they've just put in some new equipment. The staff is friendly, knowledgeable, and ready to help if needed. I enjoy the free lockers and towel service, and I do frequent the smoothie bar after working out. Free parking is available in the Veale Garage, you just need to get your ticket stamped at the front desk.
I find 1-2-1 to be a great gym for what I need. I'd recommend to my friends.