I have a 2moa aimpoint and I have been throwing around the idea of getting a magnifier also.

On the upper I am building I was going to get a decent 1-4x scope and a larue mount... for less or the same price I could do the 3x and use my current aimpoint. But how does the dot look? Will it be 3x the size or what?

You better have perfect eyes.  If you don't, it will look like a comet with the 3x and RD.  If you can look at a friends scope first, you might save yourself some money.

I don't know anyone with a magnifier.... I have astigmatism and without my contacts I can't really use it effectively. Heck, sometimes it is still odd shaped with contacts if they are dry or my eyes are irritated.

I guess it is a scope for me then.

If you have been diagnosed with astigmatism, this is a slam dunk for the scope.  About a month ago, I bought an Aimpoint 3X magnifier.  It is a great piece of glass.  I had to sell it.  With the M3, M4, and T1, the beam looked like the comet I mentioned.  With shipping and the reduced price I sold my new magnifier for, I figure this was a $100 lesson (look before buying).

I have horrible astigmatism, but I haven't had any trouble shooting my Aimpoint with magnifier out to 500 yards. The dot isn't a perfect circle, but it's close enough. The MOA size of the size stays the same, but it is magnified 3x just like the target.





I can't think of any $300 variables that are anywhere near the quality of Aimpoint. Cheapest I would go with is the Trijicon TR24, but it costs more than $300.