When I moved there the food scene was nonexistent and people in the US still perceived Pittsburgh as a bad place to be (e.g., a lady I met in CA responded with "Oh I am so sorry" when I told her I was living in Pittsburgh). CMU also didn't really understand startups - we were the first company to ever do something with a technology that CMU released to the founders.
But it was also a time where you could hire CMU CS grads for $30K/year and rent an office for 30 people for less than $2K/month. And we were a big fish in a small pond so we got a lot of local press and a first cut at the local tech talent (one of our first hire ended up becoming co-founder of Tumblr!)
After the exit I tried to get involved in the local scene. And while I found a lot of talent/ideas/start up to promote it was amazingly hard to attract any kind of money in the city. That convinced me that Pittsburgh would never make it as a hub and I ended moving to Manhattan last year.
Now my family (wife and 4 kids) hate me for that move - because even if you throw huge piles of money on rent it's hard to match the quality of life of Pittsburgh - and we are reconsidering that move.
Happy to answer any question about starting a company in Pittsburgh!