Re: Midtown Custom
Wow, the second question you pose is way too subjective to get a good answer here. The first is easier. I think the Burstbuckers are hotter than the 57s, distort easily and offer a more aggressive, growling tone. I really like the Burstbuckers I played in a Vintage Mahogany LP, which as a chambered guitar is very similar to the Midtown (but lacking f-holes, of course).
The best way to find out is to play your LP through your amp for 30-60 minutes on your favorite settings. Then unplug the guitar, take the amp to the store, and plug in the Midtown without touching any setting (except the master volume). You'll immediately hear/feel/see the difference in the two guitars and be better able to tell if it's worth the money to have the Midtown.