OK, I'm retracting my hesitation
You should totally buy it, especially for large open water
Went out today on the river and had a blast! The wind report says some 15-17 mph sustained South winds, though gusts were probably in the mid 20s. Enough to kick off some white caps, which on the only few miles long fetch means choppy water. On that section of the river that wind is enough to generate 1-2 foot "swell". Plus a lot of weekend boat traffic for the occasional "interesting" wave interaction.
The V10 indeed feels planted in these conditions and gave me no trouble going in any direction. The large surf rudder certainly helps. The V10 is a bit too long for these waves, but there were some nice sets that I could actually surf for extended periods of time. It was challenging, because the only way to do that was to go diagonally at a pretty steep angle and to maneuver a lot. A very good exercise for reading the water. I found out I could (and should) be very aggressive with the rudder, and lean a lot forward, to be able to follow and zigzag these pretty short waves as they transformed. The rear end would just slide about where I wanted it - a feeling I don't recall having experienced with the V10 Sport (maybe I just never paddled it like this, who knows). I also began to better control the edging with my legs, rather than slide passively in the seat and paddle lopsided.
OK, I did fall of twice, the first time fiddling with my water bottle behind me trying to secure it under the bungees after drinking. The second time, who knows why, just got distracted and let me get off center too much for my brace to compensate. Good exercise to practice remounts on both sides in the wind and choppy water.
I was also surprised that, after the first couple of kilometers in the chop, I no longer needed to brace pretty much at all and had developed enough of a feel for the boat's balance to begin to trust and use it. There is a very noticeable improvement in my balance every time I take the V10 out, especially when it is a it rough like it was today (rough enough to not see any other kayakers where normally there would be plenty). So there is hope for me getting fully comfy in that boat some day in the not too distant future.
Anyway, the boat indeed loves some bumps and is quite reassuring for such a slender and fast kayak.
By the way, sat for a minute on the water in the V6 too (in the calm) and that thing is even twitcher than the V10! Granted, has tremendous secondary stability but felt just as lively if not livelier than the V10 just sitting in it. Seat is completely different, more square on the v6, geared for comfort, not rotation. The V10 seat is much nicer for a ski...