There are so many hotels in downtown Pittsburgh! We have partnered with the Westin (Marriott) right across the street for a group block rate of $185 a night (before fees) for our show in June. The link is here
We also recommend looking for hotels along the “T” line. You can ride it in for FREE (unless you are coming to and from the South Hills… then its $5), and there are many hotels along the way. There is a “T” station just a few blocks and a short walk away from the convention center at Steel Plaza.