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.