We were able to take out some new Epic kayaks for the first time of the season yesterday and it was interesting to compare side by side the older style Epic's to the new designs.
Disclosure: I am an Epic Dealer and this is strictly flatwater paddling done by relative newbies. What you read below is through the eyes of people almost brand new to surf skis.
I have two years flatwater paddling experience on a 2011 V8 and several months on a 2008 V10S. By the end of last season I had gotten stable enough in the V10S to paddle it as fast as the V8 and was just starting to gain when winter hit.
As far as the V8 is concerned, I did not detect much stability difference between the old style and the new. If pressed I would say that the new style does feel somewhat steadier (if that is possible on an already super stable boat). Everybody loved it and was able to paddle it from the get go.
For me the game changer on the new V8 is the addition of the grab handles at the balance point. More often then not I have to load and unload my kayaks by myself and I have dropped them on occasion. Anything that can be done to enhance portage is a plus in my book. While the depressions under the handles are not deep enough for my fingers to comfortably encircle the handle (and I have small hands) they do allow a much better purchase on the hull when carrying under the arms (the V6 depressions are deeper). I really wish something like this could be built into the V10.
While the new V8 is a nice redesign, the new V10S blew me away. For me, the gap between the old V8 and the old V10S was much greater and the learning curve much steeper. I was just shocked at the initial stability of the new V10S. It feels more like a souped up V8 than a slowed down V10. We had several paddlers completely new to surf skis paddle the new V10S with some confidence after 10 minutes. In comparison, they were much more uncomfortable in the old V10S. I did not have my Garmin with me for exact comparisons but I can only imagine that the enhanced stability will make a relatively inexperienced paddler like myself faster.
I did not have an old style V10L on hand but we did paddle the new style. For me it felt as stable, if not more so than the old V10S. I'm small (163 cm and 69 kg) and it seems to fit me like a glove. We had a lady in our group who is a decent paddler but brand new to surf skis paddling the V10L with enough confidence after 10 minutes to take it on 2km runs without upsetting.