I have the Monarch 7 10x42s and I love them. My FIL has some 12 year old Swarovski's and the Nikon blows them away.
No offense, but this is falderal.
centershot, the Vipers are a pretty good glass - as are the Nikon. I've owned the Viper for a short time and played with M7 (a friends). If pressed I'd call it a toss-up. Should either need customer service/repair, Vortex would get the nod.