I ride 29+ sometimes… 27.5 full squish… then switch to my 69er (26 rear 29 front) then my single speed 26er. Absolutely no difference in the real world, all have their advantages but on a normal ride they average out the same.
Don’t read to much into it…. Wheelsize does not maketh the man. If you want to really notice gains go single speed and ride a 24″ and eat less pies.
Don’t think their is a huge weight saving by going down a wheel size either to be honest…. Maybe a few hundred grams but as I said, eat less pies and have a good poo before a ride 🙂
Fwiw 29 is the sweetspot for me on the stuff I ride but I suppose the full squish 27.5 does feel (and is according to strava) a little faster in tight twisty stuff.