I am looking at purchasing a good spotting scope for chasing Big Horn Sheep. Found a local guy selling a 15 year old Swarovsky ATS 65 HD 20-60X for about $2000 CAD. A new one is $3900 CAD. Does anyone know if much has changed on these scopes in the last 15 years? Basically, am I better off spending the money and buying new or should I buy the 15 year old one? Or is there something else out there for $2000 that would be better than the old Swaro but less expensive than a new one? Thanks for the help!