Check out the ATN Ultra Sight. I tried to get input on it here not long ago, but nobody seemed to know much about it. I went ahead and bought it and tried it out at the range this past weekend. AWESOME. Its a single lense, heads-up-display that projects your crosshair onto the lense. You can actually use it with both eyes open. Visible in any light or no light. Recoil proof, shock proof, weather proof. And at $150 its a steal, in my opinion.
Good luck!