I don't watch AGT, but I've seen pieces of it, most recently a week or two ago, so I remember the Top 4 acts. I also just watched them on the site.

The Top 4 were all amazing, and Michael Grimm was a forerunner of mine and should've been on American Idol instead. Jackie Evancho is incredible (but too young). But for a Vegas show I thought Prince Poppycock or Fighting Gravity would have been more appropriate (and therefore ultimately more successful as a Vegas act). But good for Grimm, and Evancho will be just fine with more experience (tho I thought she sounded better than Sarah Brightman lol).