We had a great time at the Westin. The beach there is lovely and the water is warm. The pool with the slide was fun, but it was nearly impossible to get a lounge chair with an umbrella. Towel service was easy and it was convenient to be able to rent scuba gear right there. The general stores were well stocked and convenient, and the location near Whaler's Village and Lahaina is great. The shave ice truck was an added bonus.
Two downsides to this resort. The first is less important, but the WiFi was terrible, and cell coverage wasn't great, so be aware if you're planning to work while you're there. The second is a bigger deal. This unit was described as a "2BR condo" but this is really two separate condos with a shared foyer, but their own keyed entrances. The first is a large one bedroom and the second is a studio. It was okay for us since my daughter is 13 and could stay separated like that but it would absolutely not work for a baby or young child. I don't know if the Westin has any true 2 BR units, so this is just a review of the unit I rented on vrbo.