General consensus from friends is 650b is no real difference, maybe a little more grip.
My and friend opinion is the 29er is still a “game changer”, well that’s if you’re on a good 29er.
It’s utter BS from 29er naysayers that 29ers don’t jump, don’t manual, don’t do turns.
29ers let you get away with less travel and have more grip. You end up with a bike which is more reactive and well as being more composed, that less travel helps out with jumping too.
Gone from 26 trail bike to 29er trail bike recently and it’s better in every way.