The Vortex Strikefire is much bigger than the Bushnell. What are the advantages/disadvantages of a larger vs smaller red dot?
I would think the larger one would be faster to use but don't know what other differences would be.
In my experience this is something people get wrapped around the axle about for no reason. (Or they have not ever actually looked/used one)
I have directly compared a Aimpoint H1 (4 MOA dot) to a Aimpoint M4s (2 MOA dot) side by side.
It was virtually indistiguishable to the naked eye. It actually looked like the H1 had one extra brightness setting in very bright sunlight, which to me was an advantage.
Remember, the dot isn't "real". Unlike traditional magnified optics there isn't a physical reticle there. It is the reflection of a LED on an angled lense. You can see through it.
It won't block your vision, you can turn it down to the point that it is barely visible (and thereby make it "visually smaller" and sight it in that way. The brightness of your surroundings has a HUGE effect on the dots apparent size and visibility. That is one of the benefits of the Aimpoint, it is nearly overpoweringly bright, even in direct noontime sunlight. Some of the "lesser" brands will almost be invisible in very bright sunlight. This is another reason why a 4 MOA sight might wind up being better, depending on the manufacturer and LED tolerances.
While in theory a 4 MOA dot will be "less accurate" than a 2 MOA dot at the same range because it covers more area, and therefore will be less "precise". How much of a difference can you really visually see between a 2" circle and a 4" circle at 100 yards with your naked eye?
Remember, it isn't a precision sight. It is meant for fast acquisition/low light use. If you are looking for precision, go with a magnified optic. (Or you keep fixed BUIS and just drop your view a tad and look through your iron sights, which you can set up to be much more precise than a red dot)
The biggest advantage to me with the smaller dot is it will use less power (assuming equal LED technology and power management circuitry) so you will get better battery life.