oceandiana:
Any feedback on this operation....
I've never used them, but
http://www.scubadivingmaui.com/index.html has some info. It looks like a pretty typical luxury resort hotel onsite dive shack.
"Their" boat, the Maka Kai is probably not Island Scuba's, but some other company's boat that they book their customers onto. It sounds like the Maka Kai trips are mostly for snorklers, with scuba and snuba as add ons. That generally means that you'll be going to a site more suited for snorklers than divers ---- in other words, at Molokini you'll probably be right up next to the inner wall of the crater rather than on the center reef or Reef's End.
If you are looking for a real dive boat, I'd recommend Extended Horizons, which runs from the Mala ramp in Lahaina over to Lanai. Edit: Looking at the Lanai info on the Island Scuba website, it is clear that they just book spots onto the Extended Horizons boat for the Lanai trip.
For Molokini diving, I'd recommend doing the 45 minute drive to Kihei boat ramp and going out with B&B, or Ed Robinson's, or Mike Severns.
The Island Scuba guys would probably be good for OW cert classes, Discover Scuba diving, and probably also good for an escorted dive just up the beach at Black Rock. This is just my gut feeling from having dealt with several other on-site dive shacks at luxury hotels, and isn't based upon specific knowledge of Island Scuba.