Pros
Depending on the project you're assigned to, there are a lot of technologies to play with. Most people are friendly and easy-going. The tech leads are very knowledgeable from a technical perspective. There were only a few times when there was an expectation of putting in excessive hours. The building is modern and smells nice every day. If you leave at 5 PM or later you will never have to pay for parking.
Cons
Had a start-up feel but has grown too big. Scrum teams that exceed 20 engineers in size. Projects where scope and direction change every sprint. The tech leads are not always so good at team management (they either micromanage or don't manage at all). Expected overhead is 25 - 40% every sprint. You have to volunteer for everything if you ever want to get ahead (monthly recruiting events, company-wide presentations [brown bags], consistently putting yourself well over 100% capacity, presenting company-wide sprint demos even though you're not presenting to stakeholders). Upper management loves pointless social gatherings (all-day "tech idea" events, all-day monthly meetings, waffle Wednesday, ice cream socials, etc.), which may seem like fun morale boosters until they're mandatory and you realize it's the end of the sprint and there's a lot of work to be done. You're in an open, warehouse-type environment so it can get noisy. Despite being UPMC, the medical benefits are not very good.