I would definitely go for the Junior Suite at the Sofitel. The regular rooms in the RC are tired and boring. Nothing special, though the RC does have a fantastic lobby. The Sofitel is in a great central location. Though honestly, none of the Philly hotels will knock your socks off. Just go in with reasonable expectations.
And if you haven't been before, go to the Reading Terminal Market (
www.readingterminalmarket.org) for some of the world's greatest comfort food. Go to the Dutch Eating Place there and order the Sloppy Joe and an Apple Dumpling (with heavy cream on top). It's an Amish place so only open Wed. - Sat. If you're not stuffed, get a Hope's Royale cookie at the Pennsylvania General Store and a chocolate-and-peanut-butter-covered pretzel at Chocolate By Mueller.
I'm missing Philly now!