I return to Pittsburgh often on business, and this is always my hotel of choice. After staying at it close to ten times or so, I've finally gotten around to writing a review.
This is a great hotel not only because it's super close to work, but because it's new-ish and everything is in great shape. I typically get a king suite which provides plenty of room. Features/amenities include a microwave and mini-fridge, a couch, workspace/desk and a sink area that it separate from the main bathroom. The decor has a bit of a modern vibe, which I like.
The fitness center is great - a large room with free weights and a bench, along with a treadmill, elliptical and exercise bike. The machines have individual TVs on them, so bring headphones or pick up a pair at the front desk.
The breakfast area is always kept neat and clean, with a good variety of hot and cold items. The coffee is pretty darn good, too. Newspapers (including the local Pittsburgh Post-Gazette) are provided.
East Carson Street is within walking distance and is always a fun time. There are lots of local establishments to get snockered at.
Downsides do include having to pay for parking, but this is the South Side, and parking is a bit of a premium. Also, if you don't like the sound of trains, ask to be put on the side of the building away from the tracks. Otherwise, bring earplugs. You were warned.