I looked through a Vortex Viper PST a little while ago and gotta say I'm impressed with the glass. It looks good and the EBR1 is nice. Vortex doesn't publish their twilight factor, but I wonder how it does in low light conditions...
If I were you I'd look at a Vortex Viper for your price range.
Vortex Optics - Viper 6.5-20x50 PA Mil Dot Reticle
Only thing I don't like is it has a mil reticle with MOA adjustments. That's just senseless IMHO.
Add a little money and I'd definitely go for the PST version with EBR1 and 1/10 mil click value. Again, MHO. Good luck with whatever you get!