Love the location, but not the crowds
So first and foremost, this is your typical convention center hotel of overwhelming size, so if you're looking for intimate, I would recommend this particular Marriott. There are certainly lots of reasons to stay here though:
-Location: very centrally located, basically connected to the convention center, across from Reading Terminal and steps from great restaurants (especially those in Chinatown)
-Parking: besides valet (which was around $45 when we visited), there are many parking options in the area including a parking garage right across the street and an open lot right around the corner (both are about $10 cheaper than valet)
-Staff: I had a great experience from the moment we arrived which was when we pulled up to ask about valet. The guy we spoke with was very friendly, welcoming and even took the time to go over our other parking options if we didn't want to valet. 
-Check-in was fast and hassle free
-Room was spacious
Some minor cons:
-The iron in the room was rusting so we called to get a new one. After waiting about 15 minutes, my husband finally tracked down a housekeeper to get us a new one...but that one was also rusting. We settled but are hoping that the hotel replaces the cheap irons they have.
-As mentioned at the beginning, this hotel is huge and can be a bit overwhelming. It's definitely a popular hotel for tourists too so if you're annoyed by large crowds, this might not be your place.
Overall, would stay again.