I haven't heard Maggies, but I do have a pair of ML SL3s with a McCormack amp. They were originally powered by a DNA 0.5, but when I got a pretty good deal on a DNA 1/B I upgraded. The 0.5 was definitely good enough and - while audible - the improvements were marginal in going to the 1/B. Much may depend upon the size of your room and your normal listening levels.
Enjoy
Enjoy