So...I will be in Philadelphia in mid-November and looking at Air BnB's.

Ideally would be close to the convention center.

Any issues to be aware of?

Neighborhoods to avoid?

Parking?

Safety?

Places to eat?

I've never been, so please, advise away.

Honestly, Philly can be a fun city...tons of great places to eat, lots of great history to see. 
I would recommend staying out of the subway, specifically the Broad St line....just not worth the risk. 
Aside from that, Old City, Center City, and Rittenhouse are all fun. Take a bus tour and learn about the place....visit the Fedal Reserve Bank, the US mint....lots of great things to do. 

I'm from the Pittsburgh area however I've been to Philly to visit and always had a good time and didn't feel unsafe however I didn't take the subway I had a car.

2 years ago in the downtown section I was walking on the sidewalk...there was a traffic cop directing traffic. well a car disobeyed his instructions so the traffic cop made him go to the side of the road after he  parked,  the cop rreached in and grabbed the keys and threw them down the sewer.  I was like... lol