It's the most enjoyable fight for me so far. I like the dynamic that was built up between Luffy and Kaido, and I also quite liked the creativity of not just Gear 5 but Kaido's fighting style too (e.g. grabbing Luffy with his mouth and blasting him through Onigashima). The anime also elevated the fight to new heights, so I might be biased because of that.
The fight was essentially Luffy climbing a mountain (Kaido) to reach the summit (Yonko level and ready to go after the PK title), so I appreciate what it did for Luffy's growth overall in that sense. Now if only Oda would let Luffy use the haki he learned alongside G5 in Egghead...