Not all cruise ship spas are created equal. Multi-deck facilities with high space-to-guest ratios earn the highest marks. The best spa complexes include thermal suites, thalassotherapy pools, beautifully decorated treatment rooms, private hideaways for couples to enjoy leisurely days, well-trained staff that don't hawk products at the end of each session, special access to a spa bistro or spa menus throughout the ship, and spa suites that offer a plethora of value-added perks. And, of course, every good spa also offers a fitness center with high-end workout equipment and exercise classes, plus a range of personal grooming services from hair care and facials to manicures and pedicures. Some even offer medi-spa services such as teeth whitening and Botox.