Based on mine and the comments from people here, You have a great pistol that you should enjoy.
As for practice ammo, I would buy whatever brand name is on sale, (Federal Winchester, Remington etc.), but personally, I avoid steel cased like the plaque and do not like aluminum cased stuff either. This is not a target pistol, so whatever bullet weight you find that runs well in your Shield, but I have never of one that was picky.
As others have said, any name brand FMJ ammo will do for plinking and practice.
Now, when it comes to carry ammunition you're going to get a number of opinions, all of which are probably good. Again it'll boil down to personal preference and what works best in your gun. To be honest, in mine everything I've tried has worked just fine.
I just bought one too on Monday. Bass Pro made me an offer I couldn't refuse! With a S&W $50. rebate, it was $199. out the door. I'm still a little "gun shy" buying a new gun from S & W but I will hope for the best. Last new S&W gun purchase last year was a M640 for my GF for Christmas. It fired once and locked up. Had to be shipped back for "unknown " repairs meaning they never fully explained what they fixed. On the other hand, all the reviews for the Shield 9 have been stellar.