I've been to almost all the Four Seasons and Amans on Bali. In my opinion, Amankila has the best ocean views (and is also the best all around hotel). You'll want to search out reviews on this website (they are all outstanding) and also check out www.amanresorts.com for more info.

I personally don't care for the Four Seasons Jimbaran Bay because the view looks out over the airport. Views are MOST important to me.