Good glass just like a fine shootin gun will spoil you for life!!
A few years ago IORs where great scopes, by that I mean they where a LOT cheaper than the competition! These days they are still a good scope with some great glass and a very user friendly reticle but priced acordingly.
The first 16x Has been on a lot of different guns(50BMG,308Baer and numerous 223s) since I pickt it up many years ago, the glass still has the famous yellow haze to it but funtions just like it did new. The glass on the prototype 35mm 6-24 is about as good as it get at any price...the 3-18 not in pic has the poorest glass of the bunch but still better than most other brands.