I’ve got the 138x42 JT Pro. Previous boards/boards ridden would include Zen 129, Mako 150 Wide, Spleene Session 141, Spleene Rip 135, Darko, not sure of the size.
The JT Pro has really good low end for a twin-tip board (riding a 12m Razor, windspeed 12-15 knots, my weight 175lbs, 7 years riding); I was still able to pop raileys, although low to the water, and really had to snap the abs to bring the board back under you, but still doable. Able to stay up wind in the same conditions as a friend who weighs 140lbs, rides a 135 Spleene, same kite. So yeah, good low end for riding and doing tricks. I didn’t get a chance to compare it to my session, but I think it would be close on low end, except it’s easier to pop and jump.
On the high end of things (riding an 8m rise, wind 30knots), I found there was very little spray compared to the darko I tried on the same day. The landings were less squirly than on a smaller size board (compared to my 129 zen), pop was insane, board speed felt controlled and not skipping even when I felt overpowered during the gusts). Nicest thing I appreciated was the soft, absorbent landings and minimal spray. As an aside it feels lighter on my feet than the 129 zen (couple of years old).
I don’t really have anything bad to say. I like the adjustability of some of the other drawstring style bindings some other companies have come out with, especially in bare feet, but the season here is still cold water with booties, so it is a minor thing for me.
Hope that helps out; I would unreservedly recommend this board.