There are lots of academically oriented programs in all of those cities. The 5 programs in Boston all have trained some great people, although BU has suffered a bit. The 3 Harvard programs all work you very hard. MGH is oriented towards training expert diagnosticians and working you hard. BWH is research biased but still trains people well, although not as much for private practice. BIDMC suffers a bit by being the "third" Boston program in regards to path, but it's still a great program. To be warned though, all 3 harvard programs are a bit more "fellow" driven than a lot of other locations - by that I mean that junior residents often spend more time signing out with fellows than they do with attendings.
Northwestern is a nice program without too much intensity. U Chicago is very academically oriented. Rush has a large volume and is a huge referral center for a large area. In Chicago I only visited NW and U Chi. Loyola had a wonderful chairman, Dr McClatchey but he passed away last december and I am not sure what has happened with the program since.
I know nothing about LA. If they paid residents 6 figure salaries I would have considered going there, but until then, nope.
I guess it depends what you mean by asskicking. Do mean in terms of hours and workload? The Chicago programs are more humane in this area.
