We very much enjoyed our stay at the Ka'anapali Beach Club. We would come back for sure. Overall the resort is clean, staff friendly and location great. Parking is free and ample. Wi-fi was great. If you find your mattress uncomfortable, ask housekeeping for a memory foam mattress topper.
There are groceries, fast food, restaurants, beach boardwalk, beaches, etc. all nearby. Lahaina town is at most 10 minutes drive down the road - a great place to explore.
Be sure to understand your host cannot assign you a specific room - the resort will do that on check-in based on availability and priority. As explained to us, this is a timeshare complex - owners and members have higher priority than you. You WILL get an 'ocean view' - some are spectacular - some are not (e.g. overlooking the mini-golf towards the ocean and never getting direct sun). Not necessarily a bad thing if it's to your liking. If you're not happy, talk with the folks at the front desk. Be respectful and work with them.
If you're a sun worshiper, there's a game to be played to get a lounge chair by the pool. Apparently your towel on a chair claims it as yours indefinitely. Folks were down there before dawn 'marking' their territory. We never played the game but found it interesting :-)