Update, got the Vortex VIPER PST 6-24x50 FFP MOA/MOA and took it to the range yesterday.
Had a little trouble with the PPU 145grain only grouping at 2inches. Then switched to Federal OTM 168G and had good results (3 touching at 100y when sighting in).
I will say this about the vortex Viper PST. At the same range in the same weather I have shot a gun with a brand new Nightforce 5.5-22x50 NXS and my vortex is noticeably "clearer" at 400 yards at any magnification. In fact, the Nightforce barely edged out a Millett LRS in terms of haziness/clarity.
Just stating my opinion....