My local retailer has the Harbeth sitting right next to the Maggies, literally linked to the same system. (BAT 300x, Primare 30.1CD, Nordost RedDawn) I can tell you that the Harbeth are as close as any box speaker I've come across at retaining most of the virtues of the 1.6 while adding some of their own. The highs are nearly as detailed and open with the Harbeth. But the mids are so very inviting. The Bass is simply a compenent of Amp control. In this comparison, dont even bother with the maggies unless you have at least 150W of high current.
But the kicker is this, BOTH speakers are very critical of the room they are in. If it were me, I'd take the Harbeth simply because it is easier to deal with according to size and power. The things it lacks compared to the Maggies are minimal.