Most of the dive ops that depart from the Kihei boat ramp do their first tank at Molokini and the second at a S. Maui site. If you're an experienced boat diver (comfortable with doing a mid-water safety stop and boarding an unmoored/unanchored boat), check into Ed Robinson's more advanced charters (Sunday, Tuesday (3-tank), Wednesday, Friday). They go to sites that the regular charters don't go to much, and on the 3-tank your first dive will be at the deeper sites (e.g. The Apartments, Shark Condos) that can be absolutely spectacular. On the 3-tank day, Joe and Tiffany are the guides, and they're arguably a couple of the best critter spotters on the island.
Otherwise, the south Maui operators most recommended here are: Mike Severns, Dive & Sea, Makena Coast Charters, and B&B. For south Maui shore diving, check out Shaka Doug, or contact Maui Dive Shop and try to get hooked up with Sam (she's great!).
To address whether or not it is worth it to drive from Kaanapali, I'll simply share my experience, but ultimately only you can decide if it's worth it or not. We were certified by Lahaina Divers and because we loved the guys and their boat, and stayed in Kaanapali, we continued to dive with them for a couple of years (doing our AOW along the way). Once we had about 80 dives under our belts and were becoming good on air, we decided we wanted something a bit different. Because of reputation, we chose to dive with Ed Robinson's, and began driving down to Kihei early in the morning from Kaanapali...almost every day! We felt 100% that it was worth it to drive for 45 minutes (including a stop at Starbucks) to Kihei at 5:45am.
We did that drive until a couple of years ago when we purchased a condo in Kihei. Now it takes us 15 minutes (including a stop at Starbucks) to get to the Kihei boat ramp, and we're still diving with Ed Robinsons (though we'll go with Dive & Sea or Makena Coast Charters with no hesitation). We're also doing more shore diving (without a guide), about half and half with boat diving.
What I will tell you for sure though, is that unless you're a very experienced Hawaii critter spotter, you'll definitely want to continue hiring a good guide. It can make the difference between seeing a lot and literally seeing nothing. And knowing you're seeing endemic Hawaiian marine life that you can't see anywhere else in the world, can really enrich your experience as well. Although we don't need a guide any longer, we still enjoy diving with an excellent guide who points out things that we likely would have missed (usually the super macro). And we definitely enjoy diving with our local friends since the more eyes the better!
Just been there a bunch and felt like trying something new. Thanks again!
