RE: Vanquish I vs. Vanquish II
I've got both.
V1 is flying very good, so I haven't finished V2. I can't give you a flight report, but the difference in quality is pretty large between the two. The original (IMO) is very good quality, but V2 takes it over the top. You can use the same motor and ESC, the airplanes are essentially the same, with the difference being slightly different construction, airfoiled tail surfaces, carbon gear, and different force arrangement between the two.
Finishing V2 is on my short list of things to do, so hopefully I can give a flying qualties comparison in the near future.