I love X Shadyside. The gym is so large and ALWAYS clean, which is definitely not something I can say I've seen in other gyms. The staff are not intrusive and I've taken a few of the classes and definitely been pleased with the instructors and those who were in the class (everyone is welcoming!). It's a pretty friendly environment. Age range for this gym is all over the place and I like it for that fact the most. This truly feels like a gym for everyone.
I absolutely would recommend X Shadyside. Parking is tough - sure it's on Walnut Street - but it's absolutely possible to park down a close side street and make your way there.