Hey - unfortunately I can't really comment on Oxford, and also with regards to Cambridge colleges, I only know Caius really well. Apologies in advance for the obvious bias
Also I'm only a first year so anything beyond that (especially clinical!) I have no clue about.
LocationFirst year teaching is more or less split between Sidgwick site (where the majority of your lectures and thus time is spent), Downing site (where all the practicals, dissections, PBLs, etc. plus some of your lectures are) and wherever your college holds its supervisions - usually the within the main college grounds.
So with regards to first year accommodation location then, I'm pretty certain that Caius is the closest college to Sidgwick site, as the Stephen Hawking building is literally right next to it. Meaning you can wake up 5 minutes before morning (or God-forbid, afternoon) lectures and still make it on time. People have been known to attend in their PJs!
The one negative of living away from the main college site in first year though is that you're further from supervisions (assuming that's where they're held). Also if your supervisors ask for essays to be handed in at the main college site this also means you'll have to trek. Late night essay writing + 15 minute walk in miserable weather + 8:45AM lectures = not fun.
So with all that said, I think the ideal college (location-wise) would be somewhere between Sidgwick and Downing, where you live in the main site during first year. Queens' and Catz come to mind.
RoomsRooms and facilities at Caius are really nice - all first year rooms are either new or recently renovated, and all en suite. Printers, washing machines and tumble driers are on site (also laundry is free so you'll be on lab coat washing duty if others on your dissection table have to pay up!). I don't think it's absolute the best in Cambridge though (Downing is amazing, I've heard rumours of king-sized beds...) but still really luxurious relative to some other unis I've seen.
Study SpaceThe Stephen Hawking building's rooms have nice big windows. Caius library was formally the University library, so it's pretty grand. I'm sure you can find some images of it online. Not been there much though as it's a 5-10 minute walk from our accommodation. Other libraries you can use are the University Library and the Law Library, which is also in Sidgwick site so if your college is really far you can chill there between lectures instead of cycling all the way back.
TouristsFirst year accommodation is out of the way so you won't have a problem with tourists. But go into town (King's parade/market square) on a sunny weekend and you'll be swarmed by tourists regardless of your college
Pastoral support/teaching - can't really say, as I can't compare with other colleges.
SocietiesI also feel obliged to say - Caius takes the most medics per year, so with regards to societies, Caius MedSoc is pretty good
although I guess it's quality over quantity! There are both university-wide and college societies so chances are if your college doesn't run a society for a particular sport/activity there'll be a university-wide society for it.
Best of luck wherever you apply