Kaanapali Royal was a great spot for our family vacation.
The apartment is townhouse style, so there's plenty of space for 4 or more people. The views from the balcony are great - you can easily see Lanai in the distance and the sunset over it. The living room and outdoor balcony furniture were great for lounging and enjoying the view.
The kitchen had all the right appliances so that we could do meals at the apartment. But keep in mind that there are little to no spices, oils, or other kitchen basics. So expect to buy absolutely everything you'll need to cook a meal. This can actually make cooking more expensive than planned, since you end up buying all the little things you take for granted.
The bedrooms were good with comfortable beds and linens. Bathrooms were great, especially the master bathroom with its huge shower.
The location works well - there are shops at Whaler's Village, and various hotel bars and other places to people watch. The kaanapali beach is also great - one of the best ones we visited on the island and only a 5-10 minute walk!
Just keep in mind that Lahaina is not very centrally located - so if you're doing the Road to Hana or driving up to Haleakala, it will be a longgg car ride, since it takes 40 minutes just to get to the center of Maui. I recommend Lahaina if you're mostly interested in staying put. And if that's the case, you'll do just fine - plus the best luau on the island is right down the road at Old Lahaina Luau.