I think playing VP vs (most) regular slots earns lower "rewards" [in CET system $5 = 1 pt on normal slots, $10 = 1 pt for VP.]
I first played at Borgata in Dec. of the year they opened, playing ONLY regular slots, my offers gave me a COMPed room 2 nights/week ANY day (Sun-Sat).
I don't find (13 years later) that my offers have changed. [For the last few years I play once a month there, my comps earned after each two day trip is around $200.]
Having a slot host can help in getting better comps--I play only on Fri-Sat and generally stay in a Fiore Suite.
PS: Beginning 3/1/17, the amphora lounge and buffet will cost $12.50 for Black Label players.