I was a caribbean girl until I met my husband. I had never been to hawaii until he took me to maui. Let's just say we haven't been back to the caribbean in 10 years. This cruise in May will be the first time we've ventured outside of Hawaii in 5 years. I love hawaii and truly feel like it's a second home. I had always imagined the waters wouldn't be as "turquoise" as the caribbean and that's what i loved, but i was wrong. the waters in hawaii are so beautiful and if you're lucky enough to go during whale season, i'm jealous! lol. I've also (and my husband will attest to this also) swam with more sea life in hawaii than anywhere else. We snorkeled with manta rays right off of wailea beach, honu (turtles), octopus, dolphins, giant manta rays, huge Jack fish and even saw Laverne, the resident Tiger Shark in the marina in Kona. lol.
I don't think Hawaii will disappoint you, however, I wouldn't cruise hawaii. You just don't get the opportunity to explore the islands or get a feel for them on a cruise. There's not enough time in port, as most islands there is A LOT of driving to be had (except oahu b/c you can get around via public transportation if you chose). Every single island is different. Decide what kind of vacation you are after, then pick an island. Island hopping requires at least 10-14 days for a vacation. It's not easy. So if you only have 5-7 days, choose one island. Our choice is FS Maui in Wailea, but my girl friend and her husband are adventurous types and they loved Kauai. It's all about the type of vacation you are hoping to achieve.
Hawaii will NOT disappoint!!! Have a great vacation!