NYU Stern BPE Admit 2012
LSE BSc Management Admit 2012
If you have the money, go to Stern. It is obviously a LOT more expensive, but the experience is much better than most programs in the UK (excepting Oxbridge). For Stern they even give you the option to do years abroad in places like Abu Dhabi and Singapore. Plus NYC is honestly more exciting than any city in Europe and, coupling with the whole "novelty" factor as a European, will drive you INSANE with joy.
Stern has similar placement in jobs with LSE - LSE might be a bit better since it's the best business school in London while NYU has to compete with Columbia. In that sense NYU is a bit like UCL. But in terms of instruction and business reputation, they really are quite similar in their respective cities. Top banks and consultancies recruit at both in similar ways since they're in earshots of the firms' offices.
If you are choosing between NYU Stern vs LSE/Oxbridge, then you could make a good case for LSE or (obviously) Oxbridge. But if you're looking at worse UK unis, NYU Stern is hands down the best option.
In Summary:
With Money:
NYU Stern =(ish) LSE; NYU Stern < Oxbridge; NYU Stern > Everywhere Else in UK
*based on a combination of study experience, study abroad options, international outlook, reputation, etc
Without Money:
NYU Stern < Literally Anywhere (NYU is pretty much the most unaffordable school in the WORLD)