Rabbit:
I prefer duplex reticles. I tried mil-dot (Bushnell) and didn't like it. The reticle was awfully "busy" looking when trying to pick a quail out of the shadows of chaparral in the gray light of the pre-dawn hours. Either that, or the dots and hash marks tended to blend in with the shrubbery anyhow.
I sight in my rifles for max PBR anyhow, so the amount of hold over / hold under required isn't all that great that I can't deal with it in the field with the duplex reticles on the Bushnell scopes that I use.
For example, on my .177 R-9, the maximum PBR is close to 50 yards, and the difference between the max PBR distance of 48 and 50 yards, and the drop that occurs therein, isn't enough to stress out over. I just aim a touch above center of the KZ and squeeze.
With my wife's Shadow, it shoots flat enough so that the PBR extends to 50 yards, which is as far as I care to try to kill anything with an air rifle.
In short, I tried mil-dot, but it didn't seem to be anything more than a distraction to me.
Your results, of course, may vary......
-JP
http://www.uplandhunter.net