It definitely has been discussed here before, but it will vary significantly from person to person. I personally liked it and stayed with students at most interviews, and I had great experiences with it at every school except for one. It allowed me to gain a lot of insights into each program and its culture, and I actually made quite a few friends along the way.
Some people can't handle the extra stress of not knowing what the housing will be like, though I was certainly comfortable with it (and am not above sleeping on someone's couch). If you would prefer to have your own bubble where everything is more standardized, then spend the extra money for a hotel and nobody will judge you.
The one school where I had a bad experience with a student host actually involved some racist and sexist comments, though in retrospect I have come to the conclusion that he was doing everything in his power to drive me away from that school because he was unhappy there (spoiler alert–he succeeded). I still reported the behavior to the admissions office because that's really not acceptable.
Aside from the one very negative experience, I did really enjoy the opportunity to meet new people, learn about places and programs, and save money in the process. The only person who can really decide if staying with student hosts is a good idea for you is, of course, you.