Hi qmento.
I replaced my Think Zen with a Carbonology Sport Boost. A Boost lv to be specific. As far as I know the Boost has the same hull as the Boost lv. It's just the deck that differs. (This website won't allow me to update my profile).
I bought the Zen brand new and really wanted to love it. It was to be my main downwind ski. Although it is a nice ski in many ways; I just couldn't get used to the flat hull. It had pretty ordinary directional stability and I didn't like the lateral stability profile. It has loads of primary stability and very little secondary. I think this might work well for beginners in calm to moderate conditions. However in very rough downwind conditions it just didn't work for me.
The Boost is a far superior downwind ski in my experience. I’m very happy with the Boost lv as my primary downwind and general rough water ski.
Current boats
Epic V10L Ultra, Epic V9 Ultra, Carbonology Sport Boost X LV, Fenn Bluefin, Nelo 510, Fenn XT double, Nelo 600, Expedition Kayaks Azure, Mirage 732.
Previous boats
Spirit PRS, Fenn Swordfish, Fenn XT, Fenn Swordfish S, Think Zen, Epic V10L Club, Carbonology Sport Boost LV