The EOTech has a larger field of view than an Aimpoint, but it has a MUCH shorter battery life, which requires it to be turned off when you store it. The Aimpoint can be left on full power for years without running out. So in the event that you need it, you just grab it and go. Whereas with the EOTech, you have to hit a button. Also the Aimpoint will probably take a little more abuse than the EOTech and still stay functioning, though they're both pretty tough. Also, since the Aimpoint is a tube-body optic, it can be mounted much lower than the EOTech. It doesn't matter on an AR, but if you have other weapons you might want to use it on, like a shotgun or an AK or an M1A, it is nice to be able to mount an Aimpoint nice and low so you still have a good cheek weld.
Being that you can get an Aimpoint PRO with a 2 MOA dot, night vision capability, and a mount included for $400, I would go with that option personally.