The previous poster obviously gives you a great comparison. I did not stay at the Ritz, although we did tour the property. It's beautiful, but we felt it was somewhat remote. It would be ideal for a short stay, but we stayed in Maui for 7 nights. So we really liked Wailea for its close proximity to restaurants, shopping, beaches.
On our pool days, we always sat at the Serenity pool. It was peaceful, with great views of the ocean. And we enjoyed happy hour there with discounted drinks from 3 to 5 PM each day. Service at the pool was excellent.
As others mentioned, we loved walking in the mornings, some days along the beach to Kihei and other days along the beach path in front of the other hotels. We even did some inland walking through neighborhoods, etc. popping out along some neat waterfront areas toward Makena.