Re: Need input on 2.5-16 Elite, 4-16 Viper or ..
I've got a couple Elite 6500 2.5-16x42s w/mildot reticle & capped MOA turrets. I do see a very slight fisheye effect @ 2.5x, but that is only at the very edges of the sight picture and not really noticeable in use unless you focus your eye away from center to pick it up.
Zoom range is super versatile and I think the 2.5-16x makes a great "all around" scope. Glass is nice & clear and turrets track true, although I don't often dial them on hunting rigs. Reticle hold off subtends true @ <span style="color: #FF0000">10x</span>, marked as such on the mag ring. Rainguard coating for sloppy wet conditions actually works.
Overall,I think those Bushy Elites are hard to match in their price range. Used, they'd be had for ~$500-550. If the turrets matched, they'd really be something, but Bushnell covered that with their 3-12x44 Tactical, and it's FFP to boot...