from
http://www.sounddevices.com/products/mp2master.htm:
Dimensions: 43 mm x 94 mm x 140 mm (h x w x d), (1.7" x 3.7" x 5.5")
Weight (unit only): 0.8 kg, 2.0 lbs.
from
http://www.sonosax.ch/SXM2/sxm2.html:
Dimensions : 5,75" x 3,4" x 1,6" (146 x 85 x 40mm), 0,95lbs (435g) with batteries
So the sax is a tad longer and about 1 lb lighter.
Me and another taper ran km140>mp2>sbm1>m1 vs km140>sx-m2>d100 at a U2 show once and it was very hard to differentiate the sources. You can't go wrong with either unit from a sound perspective, especially in small club/venues.
I've just found more piece of mind as a sax user knowing that I can crotch it past wands as you never know when you go to a new venue if they wand or not. You also never know when a venue decides to pull out wands for a big show or one with a seedy crowd.
From my experience, the sax will power km140s for about 5 hours on a $4 pair of Duracell Ultras or Energizer Alkalines.