BUSHNELL MP Trophy 1x32
First let me tell you where I'm coming from. I'm an 'Optics Snob', all my rifles carry expensive high quality scopes. It's unlikely I would ever buy one of these for one of my rifles.
That said a friend of mine bought one for a rifle he put togethter for shooting indoor three gun matches were the ranges would always be 25 yards or less and usually in medium to low light settings. I played with it for a wile and I must say that for the money I think it is a very nice sight, maybe even the best red (and green) dot in the sub $200.00 price range. It was very solid and did not feel cheap at all. Field of view is fine if you shoot both eyes open, if you close your weak eye you loose a lot as the rear lens is fairly small in diameter. The built-in mount is very solid but if you wish to use irons at the same time you will need to mount it on a riser block as others here have shown.
In the end my friend ended up getting a great deal on a slightly used C-More and took the Bushnell off his rifle. As he only has one AR and I don't want it I'm selling it for him in the Optics section of the EE for $130.00 shipped. It looks brand new, only two trips to the range with it.
Eye relief is infinite, there is no magnification. I can choke up on it or place my head at the buttplate, no matter. If I understand your 2nd question correctly, once the reticle is aligned on target and the weapon held there, the reticle stays on target regardless of where you shift your head.