I have that scope/red-dot combo. I've only used it for plinking at the range out to 100yds, but I've been very pleased with it. The red-dot basically just sits on top of the scope, no co-witness between them. I have the red dot zeroed in at 25 yds and the scope at 100yds. For me the red dot isn't much use past that (covers too much of the target), but the scope reaches out to 100 yds nicely.

My only "complaint" would be that with the red-dot sitting on top of the scope it seems like it would be easy to get snagged on something and break off. Also, the on/off switch for the red-dot seems pretty flimsy. Not a deal-breaker for me, just fyi.

I think Amazon has a better price: Amazon.com: Mark III Tactical Mil-Dot 3-9X42/Scope Adaptor Mount/Red Dot Combo Package: Electronics

(not sure if I can post a link or not - if that didn't come through just search on amazon for "Mark III Tactical Mil-Dot 3-9X42/Scope Adaptor Mount/Red Dot Combo". Note that the picture they have for it does not show the red-dot, but it does come with the combo.