I stay at the Islandia Marriot several times a year but always on weekends with B1G1 coupon. Very nice hotel and they really go the extra effort to please Platinum members including (upon request) a code for free internet in guest room on the weekend and Sunday NY Times (plus weekend breakfast coupons without having to request). Can't comment on weekday stays and what extra they may do for you.

I've stayed in Melville and was pleased but that was a few years ago and we generally try to stay in Islandia because it is such a nice experience.