Use the one at PHL all the time. Works great. Saves gas, better for the environment, less hassle for everyone.
Only exception I make is when picking up my 89 year old MIL. Then we park in short term and go in, to help her get luggage off of the belt.
Otherwise, PHL lot is great. Never had a problem with cell phone coverage there (or anywhere in PHL airport land). read email or surf web on my phone while waiting. Painless.