I usually stay in the Center City/Rittenhouse square when I visit. Been thinking about changing it up. The Penn Station area looks pretty and it's not far from NJ either. Any pros and cons? Gotta book my hotel asap!
Thanks for and feedback. Steoh XOI assume you mean Penns Landing? The area is also called Old City. I love the area; great restaurants, minutes from South Jersey, and easy to reach by the el for those that don't drive. A little limited in hotel choices but the Monaco and Renaissance are both very nice...also a lot of air BNB properties in the area that are very nice. Street parking is tough but there's plenty of lots in the area. I can't comment on how "provider friendly" the hotels are but they all seem very low-key and friendly.
There's also plenty of good restaurants, casual and more formal, with easy walking distance too.
Most Philadelphians would consider the entire area between the Delaware and the Schuylkill rivers, east to west, "Center City." You can walk from one to the other in 10-15 minutes so I don't think you would reach any new clientele by the switch, if that is what you were thinking.
Most traveling ladies stay in Center City or King of Prussia. "KOP." (as it is more colloquially written locally) is popular for it sports the second largest shopping mall in the U.S. and sits in an upscale area 25 miles to the north and west of Philly.
Local ladies tend to have their incall at the Philly airport area, Cherry Hill/Mt Laurel in NJ or Plymouth Meeting PA although many NJ/NYC ladies will use the latter as well.
One other area that comes to mind is "City Ave" , which has several very nice hotels and is on the border of Philly and its upscale neighbor town, Lower Merion. Short ride to Center City, if you need to be close to that, but also close to Philly's "Mainline" which is very upscale.
Good luck MatureGFE!
Much appreciated and great info. 
Steph XO
KOP can be a good area, huge mall and some restaurant choices, another area with several hotels is the Malvern area. Both KOP and Malvern may be good for suburban clients as parking and traffic is easier than getting into Center City. I can't speak to how provider friendly the Malvern hotels are, but there are plenty and would think they'd be ok. I know of one that was absolutely fine. KOP has a few that were good. I know it used to be a high LE area, some providers I know just don't over advertise their KOP visit or are very vague on the areas they are staying.