A lot of truth here. My experience at community programs as a 3rd year basically went one of two ways:
1) It'll be a hospital that only recently has started taking medical students, and they'll have no idea what to do with them. You either get no authority and get ignored by everyone, or you get the sort of 'haphazard' experience described above. If it's the former, you learn nothing and even when you're given tasks to complete you get nowhere (i.e., nurses dismiss you completely because you're a med student, the lab literally laughs at you when you call about results, etc). These places usually have no didactics, morning report, noon conference, etc. If it's the latter, things can get really weird - nurses press you for orders and don't seem to grasp that you can't give them, you might be looked to as the person who should run the next code (this actually happened to a classmate!). Yes, you may often end up being first assist, but the rotation is often an unstructured, unbalanced mess (your first assisting in the OR comes at the cost of getting any floor/dz management exposure whatsoever, you never follow up on pts postop, etc). Physicians who haven't dealt with medical students since their residency days have often forgotten what you really need to know and do as a student, and as such you usually get a bizarre experience. One particularly worthless attending once said (as he was doing my evaluation, no less): 'how can I even evaluate you guys's medical knowledge? You don't know anything about this stuff, you'll learn it as an intern.' (This guy hadn't let us touch a pt the whole rotation because of 'liability concerns'.)
2) You rotate at some 'established' community program where you see the same half-dozen diagnoses repeatedly. Anything interesting gets shipped, and many specialties start to seem more boring than they actually are because you never see cool stuff. If there is a GME program at these places, the services will often be overstuffed with housestaff and students (I once rotated on an ID consult service whose entourage consisted of an intern, an IM resident, a podiatry resident, a pharmacy resident, a fellow, and three students. Some days there were fewer pts on the list than people in the entourage.) You still don't get to do much of anything because there are waaay too many people biting and shoving for a piece of the action. Didactics may be present, but they'll be weak. Residents will actually turn you down when you offer to go see a consult or write a note - I was literally told once 'oh don't worry about doing that boring paperwork, you're a student'.
Either way, you're not really getting the experience you deserve.