I have a Leupold 3.5x10 Mark 4, M3 with illuminated mildot that is my favorite, I have the 4.5x14 and the 6.5x20 in the mark 4 series, but the eye relief changes too much between power settings for quick gun mounting to the shoulder. The Leupold 1.5x5 is a great choice for .223, but I'd like a little more for 500 yards, especially looking for dogs. Burris is a good choice and their extreme series looks good, but I don't know anybody that has one, and they are hundreds of dollars less than leupold. Don't forget the samplelist.com of swfa, for used, trade in or demo scopes.
Good luck.