I've sailed both Regent and HAL (though neither to the Amazon) and think you can't go wrong with either one. The customer service is superb on both, and I think the food is actually equivalent too. The real difference is in the up-front fare vs. the extra charges along the way. If you're going to drink a lot of house wine and take a lot of entry-level shore excursions, then Regent is probably a better value. Otherwise, I think it's hard to beat HAL in terms of bang for the buck.