I’m 6 foot with a 32″ inside leg and have ridden a medium Soul for years – 24 hour solos, gravity enduros, multi-day rides. It’s great. (Still using it as a singlespeed.)
Then I got a Stanton with a top tube the same length as a large soul – and the extra room feels better for pretty much everything.
Expanding on what chunkymonkey found, the new bike is much stiffer and better in corners. On the other hand, I’m getting kicked around a lot more and I think I preferred the flexier feel of the Soul for everything outside a downhill track. I guess it’s just what you’re used to!
If I was buying a 26″ hardtail for predominantly XC use, it would be a large soul.