The Vandersteen sound is a "box" sound, regardless of how much talk there is about them being "boxless" speakers. They utilize cabinets just as others do. But as speakers with cabinets, they are very high quality for the $. The Magneplanar sound is quite different. Definitely less "warm" sounding. You should audition it if at all possible to see if it appeals to you.
If you do consider Magnepans, you will most assuredly need room treatment, i.e. sound absorbtion panels behind the speakers. This is not horribly expensive and very necessary to stop sound reflecting off the wall behind the speakers. Room tuning/treatment of my room made as large a difference in sound as did cables and electronics.
Many Maggie users also promote upping the power significantly. I would concur. The best is biamping them. It seems to take their performance up a couple notches.
I've used Vandys and Magnepans; both have wonderful qualities, however I keep returning to the Magnepans for their larger, and in my estimation, more 3-D sound stage. They also seem to have tighter mid-bass than Vandersteens. I am using Vandersteen subs with the Magnepan 1.6's, which is a marvelous combo. However, you might be better off long term moving into the 3.6's and deal with subwoofers later, if so desired.
