CraigH,
Awhile back I compared my Leupold VariX-III 4 ½-14X50 Long Range Side Focus with my Bushnell 4200 4-16X40 in low light. To my surprise the Bushnell beat the Leupold despite it having a larger objective. You can't go wrong with a used Bushnell 4200 or 4500.
No surprise there, the Bushnell 4200's are way better than the leupolds that you mentioned. At least in my experience.
