It depends on the SMC. For example VMI is 100% military, 24/7 with no civilian students on post, and ROTC is required for every Cadet (Though commissioning is not. This year about 60%of the graduating class took a commission in one of the 5 services.) As far as more academic freedom- not much more from what I know. That would be a benefit more associated with a standard ROTC program I would say.
The best commissioning program rather depends on what you are looking for.
But from the standpoint of being a career military officer, other than the USMC (in which being a USNA graduate is frankly not that big if any of an advantage) , the Service Academies are I would say the best place to be from. The professional preparation and training received at an SA is pretty important in your first few years of service. That advantage will disappear after a couple of years though. The second advantage is sheer numbers. Just by the sheer volume of classmates, you will have a pretty valuable professional association throughout your career. (Having that network won't save you if you are a knucklehead for sure, but if you are a an ambitious and competent officer- it absolutely doesn't hurt you when you are going in front of command and promotion boards or when the Admiral is looking for an aide who he can feel comfortable with). So if you are absolutely certain that you want to be a professional officer- and you can get an appointment, then you are foolish not to go to the SA. Can you be a a highly successful professional officer and graduate from an ROTC program ? For sure- for example: VMI has produced multiple Commandant's of the USMC, Chiefs of Staff of the Army and USAF and numerous 3 and 4 star Army AF and Marine Flag officers. So have other ROTC programs and for that matter so has OCS. But far higher numbers come from the Service Academies. It's just a personal opinion and you can disagree if you choose, but having spent a career in the Army (and not a USMA alumnus), I personally would strongly suggest that you have USNA as your first choice if you want to be a career Navy officer.