Law Student Needing a Nice Suit

Help! I'm a law student at University of Virginia, and I need a suit for a job at a firm this summer. I also would hope that it will last me for quite some time. The options I've looked at so far are:

MTM - Southwick
MTM - Samuelsohn
OTR - Canali
MTM - Canali

These range in prices from about $850 to $1350. If I'm convinced it's worth the money, I'm willing to pay the high end of that range (but not much more). At first, after researching I thought getting the Southwick would be just great, but then I tried on a Canali jacket at Beecroft & Bull. I'm tall and fairly athletic, and I loved the cut of it right off the rack. After talking to the salesperson, I started getting the impression that the differences in price would amount to 1)fabric, and 2)construction. But He also indicated that Canali jacket construction was designed more for slender athletic builds -- bigger drop, etc. This is what I'm wondering: is the quality substantially different between these companies? If I get a tailored suit from Southwick or Samuelsohn, can I get it cut like the Canali was? Is there someone/someplace else that I should try? Any and all help will be much appreciated.