Just thought i'd share my 5 cents as i currently have both, 2018 (2nd release) and 2019 (3rd release) versions in 9m and managed to take them both out recently, even thought we've entered a winter season here so the conditions are not that great.
I've read few comments here and there that 2018 is "messed up" and doesn't work as well as 2017 (which i haven't had a chance to try but i assume it's very similar to the 2019 version). While i must acknowledge that there is a massive difference between the two, and i mean MASSIVE - if i didn't know i would've thought it's actually a different kite - i wouldn't disregard the 2018 as yet. I have a very limited pure C kite experience but i'd say that if you're coming from kites such as Torch and looking for a little more crossover, yet don't want to give up that C kite feel then the 2018 version is the kite you want - Compared to the 2019 it has that amazing punchy, rocket-like feel when you take off and slack is just so much better when unhooking. This is definitely because 2018 is sitting much further forward in the window over the 2019 ... i actually struggle unhooking with the 2019 but that also might be because i suck.
The 2019 version on the other hand feels much more like pivot (but not really, it's much more playful, fun and exciting
) and sits deeper in the window so it feels the low-end is better. The jumps are more floaty and you definitely get better hangtime without trying too much compared to the 2018. I also felt like there is a less pull in kiteloops with the 2019. I reckon this is because of reduced LE taper in 2019 over 2018, but i'm not expert here.
Now i have not tried the 2020 (latest) version yet but it sounds like they've increased the LE taper again, bringing it closer to the 2018 and with the added bridle option it sounds like it could give you an option of 2018 behaviour and 2019 behaviour. Which i reckon is pretty great as there is no better or worse, they're just different suiting different riding style and expectation from a kite. Would be great to hear from someone who has tried the 2020?
To sum it up - When i feel like boosting i'd go for 2019, for unhooking and more "raw" feel i'd go for 2018.