Personally, i’m not convinced there is really a lot in it.
In the early days of 29, the bikes geometery was so hampered by the larger wheels (chain stay length, BB height etc) that a 26 was deffinately better. Then the designers got to grips with modifiying frames and suspension systems to better fit the larger wheels and the 29 now performs very similarly to a 26.
Lets face it, does a couple of inches in wheel dia make that much difference? I don’t think so, certainly no more difference than say a few inches stem length, or a 2″ longer top tube etc.
29 is supposed to “roll over things easier” but i have never actually seen any scientific evidence to support this (like some drag testing over various surfaces vs 26 wheel), i suspect that generally, a 29 has a longer wheel base than a 26 bike, and that is as much difference as the change in wheel diameter etc.
There are a huge number of b*llsh*t and missinformation sources on the net to falsely “sway” people one way or another. For example, i’ve seen one vid that claims 29 climbs better because the bike travels further for one pedal revolution for example? (er, if that’s the case, just change up a gear on your 26…..)
So, in summary, ride some bikes, buy the one you like best !! simples 😉