Last week (12/29), I used the free round-trip ticket from New York to Cape May which I received as part of their holiday promotion on MyTix.
Overall, the buses were clean and on-time (the Atlantic City bus station is definitely not though - someone tried to sell me meth there during my short layover on the return trip). The 319 was busier than I expected and the quality of service is that of a standard intercity coach, with bathroom facilities and luggage storage underneath the vehicle.
The 552 (Atlantic City to Cape May) bus was significantly more interesting than the 319, not just in terms of scenery, but also because it felt like three separate routes which have little to no relationship. The northern half of the route, which is an express service from Atlantic City to Cape May Court House with one intermediate stop at a park-and-ride only accessible via car, carried air on both of my trips - there were only one or two other passengers on board on this leg (excluding myself) in either direction. The middle leg between Cape May Court House and Wildwood was the most intensely used in both directions, and was actually pretty full going northbound. Ridership between Wildwood and Cape May was roughly what I expected for a semi-rural route.