First user have compared both kites as here the user slowboat both 4 m² here: viewtopic.php?f=197&t=2403249&start=30
I now also have compared my 2,5 m² Firefly against my 3 m² and want to share quick and dirty my first impressions in about 12 knts lulls to 27 knts gusts:
First of all I really love both kites, they are really pretty similar as being both single skins in their behaviour, but on the other hand I am pretty sure to have already seen also relevant differences, similar to those also slowboat has seen:
Firefly behaviour in many points is what you would expect from its outline. It has relevant lower AR and so also the upwind is worse than Peak4, but if the wind is well in its windrange it was still good to me. Just if it is low where you are just close to get started it feels that the Peak4 goes upwind relevant earlier and better.
I also felt the much higher tendency of the firefly for flydown. But it is not an uncompfortable flydown which you have to stear against as known from most tube kites I know, but more a much higher sensiblity in the wind window. On one hand this is a bit anoying if you have to reinstall your leash or something while flying but on the other hand it also means that the Firefly felt like a brutal quick turner. I was quite surprised how "slow" the Peak4 turned in comparison and that the Firefly could be looped much easier with one hand while unhooked. I think I started to like this but I also could imagine for some it might be to nervous. The stearing forces of the Firefly are still well feel able but way less than the ConceptAir Wave, why I would recommend to anybody who is looking for a more relaxed wave foil kite to maybe better go with that one. Also the Peak has pretty low forces but at least when trying to loop unhooked with one hand felt harder to do (maybe a bit as I actually use it with a 50 cm a bit to wide bar). The rest of the turning behaviour is similar, you can variate loop size into every radius till spin.
While drifting of both kites is as known just awesome but as named before the Firefly sits deeper in the windwindow which causes especially when being unhooked (no matter what trimmer position tried in a wide range) the ride on a wave is more influenced by the kite or lets say more powered. What I liked so much with the Peak4 that you just ride the wave while you just loose all the pull from the kite didn't feel as well with the Firefly. On the other hand you can ride more dynamic powerfull with the Firefly as able to loop it permently in the needed direction with just one hand unhooked. It is a bit more about another style than about better or worse.
When doing so a few time I missed to follow the quick turns of the Firelfy with my foil so it pulled me of or the normal suicided leashed bar out of the hand. This is where the Firefly Hybrid really shines over all. Smashing the kite into the wind waves completely uncontrolled resulted always in: Sort yourself, take your time, sit on the board, pull in the leash, hook in chickenloop ... and then just stear the kite up flipping it around just with the bar, into the sky
just awesome. If it will be not just the about 5 times I tried it, but always like this, the firefly may pull me of the board as often it likes to when pushing its super fast powerfull riding style to the limit.
I was just in the about mid to lowest wind range of both kites (wind decreased when on the Peak4) unfortunately also the wind waves haven't been very well. The wind range felt pretty similar, surprisingly the one of the firefly didn't feel worse, but it could be that it is just more compfortable to ride the firefly more powered. While the Peak4 starts a very high frequent flapping when depowered, the flapping of the firefly is of lower frequency but more powerful but as said it feels that you can go significant higher maybe even above in comparision to their sizes. In the gusts the firefly felt always like asking for: "more more MORE!"
But on the other hand in the low end it doesn't felt much worse if even than the Peak4. Apart from me there have been quite some folks on the spot that was quite impressed I was able to work my 110 cm Skate XS out of the water also in most lulls with a just 2,5 m² (think limit in around 13 knts) while during most time of the session another not much heavier guy was boosting high with an 11 m² Sonic Race on a Race foil setup ... as having the same kite I now know: no need for all the kites inbetween, both seem to have a quite good overlapp also in gusty conditions with a size factor of 1:4,4 inbetween
and for me a total compfortable windrange of around 6 - 36 knts
... lets see maybe i keep one kite inbetween, just to make sure.
I will try to compare both kites again in better waves and maybe changing the bar of the Peak4 (which also had longer (original 21) lines, firefly on around 17 m)
If I realize to seperate myself from the Peak4 in 3 m² I would expect instead a 4 m² Peak4 could be a great combination with the 2,5 m² firefly to have all thier benefits in the range where they shine most:
In the lower windrange where it is more important a better upwind and on the other hand less importance of having such a perfect relaunchability as the firefly.