I owned both. Still have the virgos. (might be selling soon)The sonics are so close overall that I would almost call it a draw. The magnepans are slightly quicker and more coherent throughout their frequency range. They have the uncanny ability to spacially present large soundfields such as orchestra's. You can pick out the two violins playing next to one another. If you listen to lots of orchechestra/classical, it might be the better speaker. My big problem with the 1.6's were their ergonomics. When set up properly, four feet into my 16 foot listening room, they were just too visually obtrusive. They are light enough to move often, but may be too fragile.
Visually, the virgo is one of the few speakers that is actually nice to look at. You can put it in your living room. Several people commented that they liked the virgos in my listening room, and several commented the opposite of the magnepans. As stated above, the virgo has much better bass, and more weight. They have the fastest 'low' bass I've ever heard. I also feel that the virgo has a slightly more refined presentation, and slightly better presentation of low level detail. When set up properly, the virgo's can do the full bore three dimensional presentation like nothing I've heard. One bad thing about the virgos is that you really do have to have them in the middle of the room, 8-9 feet apart to get their full performance. I don't have mine spiked, so I just slide them on the carpet (very easy to do). The virgo also sounds pretty good in the far field, with them 1.5 feet from the rear wall. You keep the detail, but lose the holography.
In terms of amplifiers, I heard the magnepans with pass labs, mccormack dna, conrad-johnson mv-50, and arc vt100. The tube amps sounded much better with the magnepans. With the virgo's, the solid states sounded 'as good' but different.
It is true that the virgo retails for 5500 verses the magnepans 1700. On the used market, expect to pay 2800-3500 for a set of virgos depending on vintage and condition, a nd 1400 for magnepans. Virgos have been in manufacture since 1995, so try to get a newer set.
For references, check out the online 1995 mike fremer review at www.stereophile.com. Also find immedia's web site, and read their recommended speaker placement for audio physics paper.