I think it is a more accurate round than the 40 I used to have both.
I think it feeds more reliably that 40! I have never had my 31 jam for any reason ever.
my .40 did not like lights as mentioned above so it was out as a house gun.
Even though they are usually marked the same number of rounds you can usually get 16 in a glock .357sig mag saving that extra step of taking the mag out and topping it off with one more round.