We've stayed at KBH before and really enjoyed our stay. You can't beat the location and grounds, and doing a shore dive (day or night) at Black Rock is really easy from there. The hotel rooms are pretty basic, not fancy at all, but ours was clean and large, so when you considered the price, it was an excellent deal.
Regardless of who you choose to dive with, I would recommend you speak with your boat crew and let them know your experience level. Some of the operators out of Kihei will do pretty aggressive dive profiles when they have a boat of experienced folks, so it's important to speak up. People may say that Maui is "tropical diving" and easy, but every year we always have a couple of days where the diving is challenging....with current, waves, reboarding the boat, etc.
If you want to dive Molokini, you have a choice of either driving to Kihei and catching a boat, or going with Lahaina Divers and having a long boat ride down there. We've done both and honestly always really enjoyed the boat ride with Lahaina Divers as you really get excellent whale watching (in season) and gorgeous views of Maui. Now we choose to get up earlier and drive to Kihei for Molokini and S. Maui dives (with Ed Robinsons) when we stay in Kaanapali, but always go back to Lahaina Divers for our Lanai charters since those 46' Newton dive boats are soooo comfortable for the crossing (even in rougher conditions).
You won't go wrong booking with Ed Robinson's, Mike Severns, or B&B out of Kihei or Lahaina Divers out of Lahaina in my opinion.