Currently, I am an OMS1 (just finishing my first semester) so I cannot comment on rotations yet. My knowledge comes from 5 years of active duty service as a Hospital Corpsman working at a hospital on the medical side of the Navy. I have also worked very very closely with many recruiters (although I was waaaay more knowledgable about the program then most of them, so be very weary of anything a recruiter tells you and research it yourself. Not all recruiters are bad, but this is your career so don't leave it in somebody else's hands).
That being said, while working at the hospital (Naval Medical Center San Diego, aka Balboa Hospital) I saw many 3rd and 4th years rotate through and they seemed to love it. Balboa is a great hospital though and I have very few complaints about the military side of things. Most physicians I worked with were very happy.
HSCP is for anybody (prior service and civilians), but it probably benefits prior service members a bit more. It is only for the Navy and instead of paying tuition they pay you active duty pay as an E-6/E-7 with full benefits and also your time counts towards retirement while in school, and you graduate making more money then people in HPSP. But again they will not cover tuition, so it benefits people with the GI Bill more who can use this to cover part of tuition. However, if you are considering retiring in the military then this option would probably be better, because in the long run you will get more money out of the military (depending on the tuition of your school). Also, if you cannot live off of the stipend they provide in HPSP (I couldn't because I have a family of 5 to support) then this option is also appealing for this reason.
Hope this helps.