I've been testing mine now for about 3 weeks, and like I thought after my first trip to the field, I still believe it's a keeper. This thing is a blast to fly, simple as that. Very forgiving airplane.
I've tested a bunch of different props on my SurpassII, most recently the 16x4W with very favorable results. This engine is very easy to use, and has a lot of torque for a 91, It'll pull this airframe out of hover with anything from a 14x6 thru the aformentioned 16x4W. A flying buddy brought his UCD out for the first time this week and gave me some stick time with his Surpass on a 15x6, and I really liked it, that's about the only prop I haven't tried, so that'll be next weekend's test for my plane.
As for the CG debate, I started at 5", and now I'm completely satisfied at 6.25". It'll harrier completely stable at this setting, waterfall tight, land at a crawl, and do the most shocking low altitude wall to waterfall. The more I moved my CG rearward, the less rudder coupling as well, another added bonus of the 6.25" setting from the book's 4-7/8". Great Planes really has a winner here.
Eric