Dealers can do cheap oil changes because many of them don't use the oil they are supposed too.
You will most likely get an OEM oil filter but the you probably won't get Pennzoil / Mopar oil, you get oil from a drum and it is cheap garbage that I wouldn't run in a beater. They also walk most people out the door with extra services.
I would rather pay a little more, use great oil and filters and do it myself than take my chances with the 16 year old kid doing oil changes at the dealership.
That being said it's great you are happy with your dealer. You don't hear that often.