I had the opportunity to try out both the Aimpoint and the Eotech magnifiers at the SHOT Show. I was glad that I did because I could not live with the Eotech in its current configuration. Here are my observations:
1. I found the eye relief on the Eotech magnifier way too short. YMMV, but here is what I found. Even mounted almost all the way back on the rail, I had to strain my head unnaturally forward to get the appropriate view through it. It was an unnatural position and my neck was uncomfortable. I literally could feel the back of my neck straining. It was not for me. I asked the Eotech reps at SHOT whether they will be making it with longer eye relief. They said that they had received some requests for that but that there were no production plans at this time. (Heck they just came out with these ones.) I was intending to purchase one of these for my 552 so I was disappointed, but happy that I'd found this out before I bought it, mounted it, and then found that I didn't like it.
Lastly, this could not be resolved by mounting the unit further back on the rail. The samples that I tried were almost all the way back on the rail. Any further and they would have limited access to the charging handle. (It also would have precluded a rear sight.)
2. Other than the eye relief problem, I found the Eotech magnifiers were bright and clear.
3. The eye relief on the Aimpoint magnifier was longer than the Eotech. Picking up several rifles with the Aimpoint magnifier, I found I could see through them comfortably in a normal shooting position and cheek weld. It was a very noticeable difference between the two. It seemed "just right" on the Aimpoint.
4. The Aimpoint magnifier can be used with Eotechs or Aimpoint sights. I have decided to get the Aimpoint magnifier to use with my 552.
5. The Eotech flip to side (FTS) mount drops the magnifier lower on the right side of the receiver than similar mounts for the aimpoint. When talking about it with a couple mount vendors, they referred to the Eotech FTS as the "brass deflector" mount. I don't have any first hand experience with that, but they said that brass deflection was an issue according to someone's review. Maybe someone here who's used it can verify it.
6. I found the LaRue flip to side (they call it "pivot"), detachable mount for the Aimpoint magnifier to be really slick. It is a detachable lever mount, so you can easily remove the magnifier to mount on another rifle or to use as a monocular. This mount also has a pivot feature which swings the magnifier out of the way for short range shooting. I was impressed enough that I bought one on the spot. Here is a link to the mount and below is a picture of it:
http://stores.homestead.com/Laruetac...ail.bok?no=131
If you have the opportunity, I recommend trying them both out while mounted on a rifle. It made a big difference in my decision.