Can't comment from experience on the Kona hotels, but here's what I know first-hand about the ones you mentioned for Honolulu:

My first choice would definitely be the Moana Surfrider. It's centrally located, decent beach area and a classy hotel overall. I would opt to stay in one of the original "classic" rooms - but be warned: no closets in the rooms. I'd lump the Waikiki Beach Marriott Resort & Spa, Sheraton Princess Kaiulani, Sheraton Waikiki, and The Royal Hawaiian into the same middle-grade category. Nothing special, nothing bad.

The W (in my personal opinion) doesn't make much sense in Hawaii. It's not on a beach -- it's across a parking lot from a beach. It has no pool and it's a good ways (10 minutes or so by car) from Waikiki. The interior of the hotel is fine, but nothing great. Based on what you say you're looking for, I'd avoid the W.

Hope you enjoy your stay!