i had a yukon gen1 scope (the waterproof one, never tested that thow) and it was OK, nothing special. it was 2 or 2.5X magnification, i dont remember but one thing that was annoying was that the depth of focus was tiney! i would say that only a few meters were in focus at one time. it cost around £160 which was quite cheep at the time.
about a year later after next to no use the image started to flash brightly like a strobe light. i dont know what caused it as it hadnt been droped etc.
in fact it was very carefull with it. so as it was still under garentee i sent it back after an e-mail saying they would replace it.... over 6 months and many more e-mails later which had mostly gone ignored they sent me a replacement hopeing to shut me up. it didnt even work
another few months of frustrating e-mails and they eventualy admitted they couldnt give me one because they had gone bust and sent me a second hand zenit NV scope which is actualy worse than useing your eyes alone at night. was not a happy bunny
im not sure if yukon has changed hands since but i wouldnt get annother one. unless you can get a military grade scope cheep i wouldnt bother.
pete