Primary Arms has been good to me. As others have said, if you want magnification, you're better off getting something like a 1-4. But, it is a scope so you have to deal with eye relief where you don't with a red dot. The red dot is for fast target acquisition, the scope for precision. Not saying you can't shoot groups with a red dot, just saying you'll likely be tighter at 100 yards with a scope. My advice, get both. And get an AR for each.
As for the red dot and a front sight post, you pretty much forget it's there until your battery dies at the range. Then you're glad it's there. I also just got a PA micro that should be here Wednesday.
Primary Arms 30mm Red Dot
Primary Arms 1-4 Scope