We split our stay between Aulani and MBC in April. When we decided to go back next week we were torn on where to go. Ultimately we decided Aulani because we are only going for 4 nights and will only have a rental car for one day and we want to be able to walk quickly to dinner at the four seasons and monkey pod and I want to paddle board quite a bit. We love things about both MBC and Aulani. What we like better about MBC is that is is easier to get a chair at the pool, they have the best frozen mai tais, they have fun games (corn hole, etc) in the lawn by the pool and we could rent a cabana at the pool for practically nothing. The pool is a fun pool that feels like its built into a volcano. Lots of fun hot tubs and waterfalls and different levels to the pool. we also like the lagoon a little bit better at the MBC.
What we like about Aulani is the lush gardens, the hawaiian music they pipe in, that you can rent a paddle board, free sand castle toys, and proximity to the Four Seasons and Monkey Pod and ABC store. also the Disney characters etc.