i, myself, question spending lots of $$ on glass but that is one a reason to do so. i think get the best you can afford. the last scope i bought was the pentax lightseeker with the 30mm tube. i think it was around $450 so heaven help me if it fogs up. i will say i have less expensive scopes and not had a problem with them but who wants to find one while a 14 point buck is standing there.