I'm a massage therapist and the most popular treatment that I do is hot stones. Extremely relaxing, great at helping to relax but also eases muscle tension. I think hot stones is definitely more of a treat in terms of a gift for someone, so I would say go with the stones!
@SmiledWithTheRisingSun One stroke with a stone is worth ten of the hands and the treatment is ten times more effective and deeper than manual massage. Heat treatments take away muscle pain far quicker than manual massage. So not surprising that some physiotherapists also use heat when treating patients.
Many of my clients who tried hot stones as a one off, have never returned to manual massage. Its by far the most popular treatment that I do. Funnily though that it's not what people expect - as they see photos of people lay with the stones placed static in a line down the spine and assume that there is no massage involved - huge misconception but one that I can understand. There are also studies on how hot stone massage impact stress / relaxation and even auto-immune diseases. Definitely not a gimmick.