Fantastic review and thanks for taking the time to share. I too have had a Nano and recently got my shield after waiting. I also have had a keltec pf9 and currently own a kahr pm9. I too think the shield is great but the trigger seems to be difficult to feel just before it breaks, reset is awesome, quick as you would expect. I never had any issues with my nano and really wish i had it back, i will probably ger another one. It is anlittle slide heavy which is probably what hurts it's point to shoot ability but that is the only area it suffers in, in my opnion. The kahr is fantastic as well, small and easy to conceal like the nano. That is the only downside the shield has, its larger than the others. Oh, my nano ate anything i put through it with no issues....i really miss that little gun.
Again thanks for the great post