I just got my 9mm shield and shot it today. I'm a Glock lover, but I've got to give credit to S&W for this one. No problems in my first 150 rounds, shooting WWB and Speer 124 grain.
Likes: big gun performance/features in a small package. Recoil was pretty much non-existent, and the gun was a joy to shoot. Maybe that's just because I'm used to shooting 40 S&W. When I handled the gun (empty), it felt somewhat top-heavy, and I was worried that it wouldn't feel that great while shooting it. I was wrong! Also, there's a lot of negative reviews about this thing having a safety. As for me, I like the safety, and I found it quite easy to disengage with a slight flick of the thumb. It seems harder to engage than to disengage.
Dislikes: Loading the magazines was slightly harder than my Glocks - I think it's a combination of a fairly heavy spring, and the fact that the metal magazine walls are fairly thin.
Misc observations: 6.5 pound trigger is a bit heavier than my Glock 22/23. Also, I noticed that the extender on the 8 round magazine is free to slide up the magazine. I didn't have any problems, and it's easy to push the extender back down to the base of the magazine. But it made me think - what if that happened "real world" and I tried to quickly load it in the gun -- would it prevent me from loading it? Probably not, but it's something to consider.