haha, hmmmm, i could very well be wrong (or misunderstanding you..?), but from what i know uk med is a 5-6 year undergraduate course and us med isn't very easy -- if at all possible? -- for non-us citizens, soooo idrk. do people usually go overseas for med where you are? virtually everyone i know from hk/ singapore who wants to go into medicine (and law to some extent) all rejected the likes of harvard / stanford / cambridge to study medicine locally, lol. it's more convenient, fewer conversion requirements, etc etc..?
i'm no expert on the grad stuff here either, but i can definitely say the undergrad natural sciences course i'm doing is fantastic. to get taught -- let alone so frequently -- by someone like peter wothers is really one of those never-in-my-wildest-dreams-could-i-have-imagined things, lol. supervisions are amazing too - we meet with supervisors in groups of 2-3 once a week for each of our four courses. it's hands down where i've learnt the most, and it's something that's unique to oxbridge, apparently, so if you're considering going overseas for undergrad studies at all.... not that i'm biased or anything!! x)
as for natural sciences, if that's what you're looking for, you'll be glad to know it has breadth for sure, haha. in first and second year we pick three or four from a number of courses (like eight in first year and twenty?? in second), and as someone who wants to go into research, but isn't quite sure which area specifically, i'm really loving the opportunities to explore and keep my options open -- although it does sometimes feel like i'm trying to do three undergrad courses at once!! - we probably go into enough depth with every one of those subjects to be doing a whole degree just on that.
don't know as much about math, except that it's supposedly insanely hard :p. economists and mathmos come down like a week earlier than everyone else (before term starts) just for math courses from 9-5, people cry, and people switch out to natsci; happens every year, or so i hear. good times~