I guess everyone's experience varies but I prefer Springfield.
Below are my experiences with both SCs:
Springfield SC: Arrived at work in Summit, NJ with a screw in my tire (tire was not losing air). The SC offered to come to my place of work to pick-up my car, do the repair (tire replacement) at the SC and drive it back to me. Additionally, they mentioned there was a service bulletin for my build related to adjusting the camera pitch on the front-facing camera (AP2) which they updated. This was all done on the same day without a service appointment.
Paramus SC: Brought my car in because the rear passenger-side door handle was behaving oddly (handle would present as normal but there was an odd delay in the door opening when pulling the handle). Arrived at the SC in the AM and showed the technician. Around 4PM was told the car was ready. Upon arriving at the SC, I was told that the handle in question was operating within specs. They also mentioned that during a courtesy check, they found an issue with the rear driver-side door handle (which I thought was working perfectly). I get home and test both doors. The rear-side passenger door still has the delay (no surprise there since they didn't try to fix) and now the driver-side passenger door makes an odd vibration sound when closing the door. This wasn't there prior to the visit. So now I have 2 rear doors that have issues. This was back in Nov and I haven't had time to bring it back in. They also gave me an ICE loaner which at the time I really didn't mind but looking back made the whole experience sting a bit more.
Needless to say, I will probably use the Springfield SC in the future even though its a further drive from home.
Both SC's were very good at keeping me updated on progress (via text messages).