Congratulations! Wharton is a pretty amazing opportunity in terms of recruiting into tech on the west coast - they are doing a lot! Unfortunately the schools are not really peers but I understand the London focus and that's great. I would say that this is your one opportunity to do something different and be outside of the US/travel/etc because then loan payments kick in, family, mortgage, kids, and you are toast at the point. You won't be able to take much time off until you are 50+. At the same time you need to really figure out how much London matters to you. I know most people who are graduating after 2 years of poverty and not having a job, are pretty fed up with a student lifestyle and all of that romance and want to get into a solid job that allow them to get a good footing and help start paying off their loans.... few are thinking of a hiatus in Europe.
As to LBS - yes, strong in London but has a bit of a limited/unknown name in the US. I feel the biggest unknown will be the ease of employable with the work permit after graduation. I have not seen any indicators that it would be tightening and I believe LBS is Tier 4 in the UK which provides a lot more freedom with recruiting. I would just double-check on that. If your goal is to be in London, then LBS is the good option. My cousin is going there in the Fall and that was his first choice (he did not have Wharton offer though, only a WL at Darden). At the same time, the caliber of students and the size of the program, employers that come on campus, class choices, are far superior to what you will find at LBS. How to value that? Not sure.... but it would be much harder to get a Work Permit in the UK with a Wharton diploma than LBS and the company hiring you would need to jump some hoops.