A Medical degree whether it be a BMBch, MBchB, BMBChir or BMBS are all equivalent in standard, since all graduates are accreditted. The difference lies in the style of the course, be that traditional or intergrated or PBL. which one you go to should depend more on you're preference for course rather then the name.
It is true that some people prefere to suffix their name with Cantab, or Oxen, as opposed to say Notts or Dundee to take the example listed above - however assuming on the whole 50% of doctors go on to be GPs, when was the last time you asked your doctor where he/she graduated?? if ever?
Also I think league tables are not entirely reliable - how much can you compare a traditional course against a intergrated or PBL course? they're compleatly different teaching styles - not to mention each institution would be inspected by different teams...etc...the variables are enormous.
Wangers