The EOTech 512 is a good little optic. The use of AA batteries makes it much easier to replace when the time comes. The lack of dedicated night vision setting makes it cost less and most of use don't need that feature anyway. Some don't like the switches on the back, but if you don't have a magnifier, it's a non-issue.
All the EOTech optics have a 1MOA dot with a 65MOA circle. This excludes the versions made for specific purpose guns like grenade launchers.
The smaller the dot, the more precise it will be. However, a 2MOA dot is plenty small enough. At a recent class, a shooter with an Aimpoint Comp M3 with 2MOA dot, out shot all of us. So, it's not always about magnification.
By setting the illumination setting as low as possible, but still visible, the dot will be as small as it can be. This helps with aiming and precision. A 2MOA dot will cover 2" of the target at 200 yards. That's plenty small enough to do most shooting.
Also, go to a local store and look at the optics first. This is what the EOTech reticle looks like to most people:
In that image, the brightness is set way too high. Bring it down about 5 clicks and it will look like this:
The ring will look a little fuzzy. That is normal. This is because it is drawn by a laser similar to how your TV draws the picture.
The Aimpoint dot will be larger, but will not look fuzzy. This is due to its being a single dot being projected by an LED.