If you're going to be wearing light clothing (i.e. shorts and t-shirt) than get the G27. If you are generally going to be wearing a little bit more clothing than that, then get the G23. I have a G23 and it would not be hard to conceal in a shorts and a t-shirt. But, a G27 would be nicer if it was for ONLY concealed carry. The .40 cal round is a round to have much confidence in.