Looking to buy an aimpoint red dot w/Larue mount, probably going to go with a M2 or M3 not sure yet, but I was wondering whats the difference? advantages, disadvantages of the Larue LT152 RAS II mount compared with the Standard LT150 mount?  In my reading it looks like the LT152 is lower but didn't know which one to go with.  I plan on running troy flip ups, didn't know if height of mounts are important for leaving these on...  Any advice??

** Does M2/M3 both come with extra battery compartment??

I have the LT 150 and it has battery compartment.  It is the mount extend forward.  It allows co witness of my Troy BUIS in the  lower third of the field.  I just added a Burris AR tripler ( 3x magnifer) in the Larue pivot mount.  The Burris unit costs about 1/4 that of the Aimpoint magnifier and seems quite good.    I just installed it last night so have not had a chance to try it out.   Burris supplies a long screw that you use to spread the Larue ring to get the magnifer through the ring, and it takes quite a bit of spreading, but it works.

I went with the Aimpoint ML3, do not need night vision, so was advised not to spend the extra for something I would not use, but to get a good light, and the combo is fine for anything I would ever do.  Specs on ML3 were a little better than the ML2, at least in area of battery life, so that was the reason I chose the ML3.  Given a 50,000  hour battery life on low setting, plus 10 year shelf life on the battery is a plus, especially since I will keep one on and set up for home defense.