UAG Red dots

[SgtUSMC]

Anybody have any first hand experience with UAG Red dots?  Cheap with a lifetime warranty.  One of my buddies said he uses one, and that  I might be surprised.   
Most of them look like they're made by the same manufacturer, then different companies slap their logo on them.   

Figure at 40 bucks I'd give it a shot.  I know its no Burris, but will it do its job is what I'm wondering