I’ve got a 5 29 S and think it’s ace. The feel of the bike is very similar to my old 26″ 5 and it doesn’t feel it’s size at all.
Same pros/cons as all 29ers Vs 26″ i.e. it’s very, very fast and smashes anything you stick in front of it. It does everything the old 26″ did and does not make any harder work of it, including tight switchbacks. It’s not quite as much ‘fun’ as the 26″ though, given the right situation. You go out for a ride on it rather then go out to arse about if you know what I mean.
I can’t really see why you’d get a Gyro over a 5 29 as the 5 29 will cope easily with virtually all types of riding and gollops the miles as a cross county bike. Keep an eye on the Orange website as my mate got a one ride old ex-demo 5 29 S with repainted front triangle for £1800.