I actually was considering the 38EC vs the 37SS, before I ended up with a different Formula.
Boats are the same in that construction, materials, workmanship, etc is superior in both.
EC in my opinion is a performance boat with the emphasis on speed vs. liveability.
The Formula is a performance boat with the emphasis on liveability vs. speed. In the end both are awesome boats, if you really want SPEED, the EC is the way to go. If you want a great boat, that you can really weekend on frequently, and also goes pretty fast, get the 400SS.