Plenty (hundreds) of medical students and residents in the Guard and Reserve. I would be cautious staying on the enlisted side to test it out. If you're enlisted, the combination of being lower rank, having a real job, and being deployable is going to make the experience different and possibly more painful. You will likely have to commit for 6 years given the new commission and likely be expected give up a summer break in medical school to go to COT. For most people, I think 6 years as a medical student/resident officer is a lower risk trial than 1 year as an enlisted member. You can be a medical student without being in any special recruitment program.
The experience is going to be highly variable based on your command, your own motivations, and your willingness to push back. I've seen drill be anything from studying in a corner to being assigned as a platoon leader. The variability does seem to be higher in the Guard and the Reserve has some extra drilling options if there is no unit with a need for your specialty within a few hours drive of you. Really though, that choice comes down more to your specialty and what kind of military medicine you want to be involved in. The Guard is going to be geared toward operational medicine, disaster response, and "front-line" specialties like primary care, emergency medicine, and flight medicine. The Reserves are going to be geared toward sub-specialty care and either deploying to larger established medical centers either in theatre or back-filling in the US.
I would recommend scouting out the unit you would potentially join and talking to them. I would expand your search to both the Guard and Reserve and to at least both the Army and Air Force. I know nothing about the Navy Reserve. For Guard and Reserve, finding a good unit is way more important than the specific branch that unit is in because you're not shifting around every 2 or 3 years and neither are most of the people in the unit. It's not rare for people to commute from other states to stay with a solid unit. Talk with people in the units that would potentially be gaining you and find out what their expectations would be and what previous medical students and residents have done during drill.