marchboom,
The mildot reticule, ballistic plex, and varmint hunter reticule appear to be similar but do not function the same. The basic explanation for all three are as follows.
The mildot is designed as a range finding reticule with the mildot spacing = to 3.6" at 100 yards both in the vertical axis and the horizontal axis.
Leupies varmint reticule and Burris balistiplex reticles are more of a range compensating reticle. The cross hairs are preset based on certain caliber bullet weight at certain velocity will impact at certain point of impact and the lower horizontal cross hairs reflect those points of impact.
I personally prefer the mildot reticule and have four of them and use them for ground squirrels (whistle pigs), rock chucks, prairie dogs, coyotes, and big game. The first one I bought Leupy 6.5 X 20 X 50 LR is mounted on my Rem 700 VSSFP in 22-250 and is my long range varmint gun (500 + yards).
I have two Nikon Buckmaster 4.5 X 14 X 40 SF mildots mounted on my ARs in 223 and 17-223 which are my calling rifles.
Last one is a Sightron I 3 X 9 X 40 on my 308.
For the money the Nikon Buckmasters are hard to beat. The glass is crystal clear, adjustment is repeatable, the side focus is great, and you can't beat the price for the quality. This got a little long winded but I hope it helps out.
BoomSplat