Great stay, great location
This was fifth hotel I stayed at with my wife on our honeymoon-roadtrip and it was definitely a nice hotel, we had a great view of Philly and the room was large and luxurious. We were in Philly for Independence Day so it was an interesting stay. Only minor complaints.
Presentation (4/5)
Overall the room was excellent, very luxurious and clean. I wasn't a huge fan of the shower, but that is minor. One thing I found weird was while the lobby and rooms were air conditioned, the hallways of the hotel were not. This isn't a big deal, but a bit strange when exiting the hotel you go from cold, to hot, to cold, to hot again (outside). I understand that this is probably to save energy, so I guess it's OK. 
Service (4/5)
The service was good at the Omni, none of the staff were overly friendly but they weren't necessarily rude either. 
Room Service/Dining (N/A)
We didn't eat in the hotel, we only stayed one night and didn't really have the time.
Location (5/5)
The location of the Omni couldn't be better, right outside independence hall. We had a view of the park and the water, very nice. We also got to see fourth of July fireworks in our room, great location.