My interest is in Oxbridge medicine - sorry its a bit niche. But just wanted to inject some data and just a little opinion to the thread in case its useful to anyone.
FY1 jobs are currently allocated by a national system. Oxbridge, Imperial, UCL score highest on average. There are, however, major advantages to going to less well scoring unis, as currently a major part is by which decile you are in within the med school, and its easier to be a high decile at other unis. foundationprogramme.nhs.uk/sites/default/files/2019-07/2019%20Recruitment%20Stats%20and%20Facts%20Report_0.pdf
The speciality chosen seems to vary by uni. You are substantially less likely to apply to be a GP if you go to Oxbridge, for example (probably not a good thing on a national scale!). foundationprogramme.nhs.uk/sites/default/files/2019-07/2019%20Recruitment%20Stats%20and%20Facts%20Report_0.pdf
Doctors exam results are all published. Oxford and Cambridge do substantially better in both the written and clinical/communication exams. About half is thought to be due to them recruiting smarter people to begin with, about half is due to unknown factors i.e. probably the uni's teaching. www.gmc-uk.org/education/reports-and-reviews/progression-reports
bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-6-5
Going to Oxbridge probably does help you if you want to exit medicine, both in terms of going into research and in terms of going into the city or whatever. It probably is helpful if you want to go into private work - patients there get very snobby - and it is definitely helpful if you want to work abroad in many countries. For example Singapore actually releases a list of acceptable med schools, which includes only about half of UK unis! www.healthprofessionals.gov.sg/docs/librariesprovider2/default-document-library/second-schedule---registrable-basic-medical-qualifications.pdf
Anecdotally, Oxbridge is noticeably harder work. However, it has substantially more resources to look after its students with and holidays are a lot longer in the first 3 years so it is necessarily more intense.
There seems to be this notion that if you have early clinical contact its completely different to 'traditional' courses. Actually look at how much 'contact' they actually mean - it is often something like one afternoon per fortnight, or a single one week placement then back to the lecture halls - its not like how I would envision it! And even the most traditional do have some clinical contact early. It can be as little as an afternoon every 8 weeks (Oxbridge), but that might actually not be so different!
I actually think student satisfaction ratings are very telling, as long as they are being consistent. For example, Sheffield always does well, King's always does abysmally (bottom for 6 out of the last 8 years, and 3rd from bottom for the other two) and some of the anecdotes of how they treat their students are shocking. If it was my dc, I would be avoiding King's based on that alone.
BUT these are all relatively minor considerations. Most important is 1) will you get in - that's the difference between being a doctor and not, and a good 60% of applicants get in nowhere at all, and 2) Do you like the course structure - medicine is, contrary to popular belief, incredibly varied in terms of its course style and also content and you'll be doing it for 5/6 years so you better like it! Only after that, do other considerations come in.
I got no help at all when applying to medicine all those years ago, and I feel that even those that profess to know a lot, actually can have false impressions and be out of date. I had no idea FY1 applications were so standardised, I had no idea that the courses varied so much.