I replaced my 2014 7m evo & 10m dice with 7 & 9m 2021 Pivots this last year. I have also had some time on 2015 and 2018 dice. I have not ridden the 2021, but the 2018 was the step change I believe.
Responsive to loop = Dice loops bigger circles and bigger pull. Weeee
Higher boost = 2014 was bad jumper but the 2018 Dice was very good, but Pivot is maybe a little more and amazingly easy to access.
Hang time= Pivot
Dice loops always pull, consequently this chicken wing would not pull the trigger in as high of winds. I liked how you could work the dice to generate power and I think it drifted a little better. Steering while drifting not as sharp though.
The insane top end wind range, easy big boosts and fast "pick your power" loops make me happy with my choice. For foiling, it's behavior in the lightest of winds (sub 10kts) leaves some room for improvement (will forward stall), but then my dice 10 got unstable and surged
around 30kts and the 9m Pivot is happy in 40+. Not sure why I bought a 7.
Again, most of my time is on a 2014, so we are talking nearly a decade of kite improvement.