I have the spirit ED's which is basically the same glass as the Endeavor, but in a different housing. To be honest I just really didn't like the look of the Silver in the middle of the optics. Anyways the focus wheel is super sensitive with very little resistance it is still fluid, but just moves really fast if you are used to how stiff Vortex optics are. As far as clarity goes I feel like the glass is exceptionally clear for the price range. I have never had to use the lifetime warranty, but they do include a laminated warranty post card with the purchase so I am pretty sure they are serious about he warranty.
I don't think the warranty is transferable from owner to owner, but then again how are they going to know you are not the original owner? I feel like you give the Vortex resale value because of that but what you get is superior glass for the price range. I can comfortably glass for longer than I could in my Vortex Diamondbacks. Durability wise they have lasted for close to 2 years now and I consider myself to be exceptionally hard on things.
The twilight factor is what sold them to me.