The summer after graduating from college, I volunteered for three weeks with Projects Abroad--Medical Project in Jamaica. I thoroughly enjoyed my time working in the medical clinic, where I was able to observe nurses, midwives, doctors, and even a nutritionist work with the local people. "Hands-on" work is generally limited and depends on the location of placement, but I was able to have more direct patient contact experience the last week/week and a half I was there, due to becoming more familiar with the system and the medical staff being confident in my abilities. I really enjoyed observing the various doctor-patient interactions and going on house-call visits with the midwife. I feel like this was definitely a worth-while experience, but those planning to eventually pursue a career in medicine and are hoping to gain a substantial amount of "hands-on work" should really talk through with their trip advisors and make sure they are being placed in a setting that best fits their requirements.
As for living situation, I had the best host family. They made me feel at home and did everything they could to be as accommodating as possible. I was also living with one other volunteer for most of the time (which I highly recommend). I also recommend staying for a minimum of four weeks, not only to be able to explore the country adequately, but mainly so that a sense of routine can really be fostered at the placement site and you can maximize your time volunteering. I really hope to return some day!