Super location; boo on the extra fees
Booked two nights via Marriott points. I'm a Marriott silver member, but didn't get one thing for being a member other than a nice welcome from the front desk clerk. 
We drove into Philly from Boston, so I was very appreciative that the hotel mentioned on its website that people driving in should use the Filbert Street address instead of the Market Street address. Thank you, Marriott. 
We arrived on a Tuesday evening, the last week of June. The hotel is HUGE (1400 rooms) and was running amuck with business travelers and tourists. It's a short walk to the historic Independence Hall and Liberty Bell area, and directly across the street from Reading Market, which is Philly's indoor food market similar to Quincy Market in Boston. There is a Starbucks onsite, as well as a Hertz rental car place. The Big Bus open-top trolley also has a stop at the Marriott, so it's super convenient for doing tours. 
I loved the location of the Marriott. If you do a tour, it's very easy to get off and freshen up in your room. Just catch the next bus in 30 minutes. We visited 4 hotels in 9 days and this hotel was my favorite, both for its location and because we felt like we fit in. We were on the 11th floor, so we weren't bothered too much by outside noise, but I could see that it could be a problem for the lower floors.
The room itself was clean and well maintained. The beds were comfortable. Their shampoo and conditioner is nice, but not sufficient for 2 people, let alone 4. 
Staff was all very nice, especially the valets and front desk clerk. The area around the Marriott got a tad sketchy after dark, though we never encountered any problems except the usual ones you'll find in an urban area (homeless people, people begging for cash). Taxis are plentiful, but we hoofed it.
We ate at Smokin' Betty's, which was recommended by the concierge. Good food, though a tad loud. 
My biggest complaint here is about the extra fees. $12.95/day for internet service is ridiculously high. Most restaurants give free wifi these days; it's time the hotels followed suit. And $45/night for parking is as high as I've ever paid anywhere. So a big thumbs down on these additional, highly inflated, fees.