The mariott downtown is in a great location. Its about a 15 minute walk to the Rocky stairs and about the same to Old City and Society Hill area where you will find the Liberty Bell, Independence Hall etc... Bring good walking shoes as its nice to walk and take pictures of all the old buildings and monuments. From the hotel I suggest walking down 12th street towards Chestnut or Walnut, and walk down either of these, much nicer walk then taking Market street.
The Room was clean and modern, I would stay here over the Courtyard Mariott, use Hotels.com to book to book for huge savings, if you have never used Hotels.com you don't know which hotel you get until you confirm but if you set your perameters for 4 stars or better, than you will get this one or another good one downtown. We saved soooo much money, by booking this hotel through a discount site. The bed was so comfortable, staff friendly. There is parking at the hotel but use this site called Parking Panda and you can save 60 % on parking costs, we had a short 5 min walk from the parking garage to the hotel, was worth it.
Didn't use the pool, it was indoor and not very big, and I prefer not to use indoor pools.
The only complaint about the room was that the bathroom ceiling was pealing off from condensation, but not really a big deal.
We didn't eat at the hotel as there are many great places to eat in the city instead.
Use the concierge as he is very helpful in suggesting places to go.