I've been going to this place for a few years now and they have yet to let me down.
Of all the dental offices I've been to in my life, this is the only one I did not dread. Everyone working there is very professional and friendly. Cancellations and rescheduling have never been a problem. They are sympathetic to working professionals that have changing schedules. There is very limited parking in the rear of the facility. I believe only 3 or spots. Street parking is not that great either so you may end up having to park pretty far. My only significant gripe is that the Orthodontist is only available on Mondays.
If you're looking for a dental office in the Hillside/Elizabeth area with great client service, it doesn't get much better than this.