Have shot competitively in SS in 9,40 and 45.also find the 40 the best of both worlds. Have a Sig Elite in 40 and just picked up a STI Sentry in 40, planning to use that as main gun this year.
I personally would lean more toward the STI. In 1911s the 40 seems to be lost step child and a lot of companies don't plan on making them except special order. A shame, Sig ALLEGEDLY says they are coming out with the competition ready MAX in 40 but we all might be retired from the game before that happens.