If you are looking for a cheap but, good red dot I'd say that a Lucid HD7 is a pretty good choice. (
http://www.shootingillustrated.com/4254/lucid-hd7-red-dot-optic/ )
I got mine for $199 and it was better then I expected it to be. I have it mounted on my LR-308 AP4. I can't say anything about long term use since it's a pretty new company but, it's worked really well for the couple months that I have had it so far. I have an old aim point Comp M-XD on a different toy that has servered me well for years and years but, at a third of the price the HD7 is hard to beat.
They are also coming out with a 2x-5x variable magnifier which I'm on the pre-order list for. (
http://www.mylucidgear.com/magnifiers.php )
My plan is to mount that behind the HD7 with a LaRue QD pivot mount so that my magpul pop up buis can still be used if needed without having to remove anything from the rifle. That way I'm pretty much setup for anything close to medium range and red dot failure if it happens. That's the plan anyways. My one concern is that the buis won't fit under the magnifier. It should but, I guess I'll find out for sure soon enough.