No experience at all with the UHD series, but over the last few years the Razor HDs I’m familiar with, both binoculars and spotting scopes, have been running a 90% failure rate, including my 10x42 binoculars that have been replaced twice and my 1st Gen. 20-60 x 85 spotter that never worked worked from the day I bought it, went through 3 eye pieces trying to find one that would zoom in cold temps. (But Vortex did admit that those were junk and finally replaced it w a Gen 2) I could go on and on about various friends bad luck but let’s just say I don’t have enough faith to shell out money for UHDs because they put marginally better glass in them.