Really fancy a niner but have been put off 29ers by my Surly KM experience. Felt great for xc but was slow, unresponsive and felt like it wanted to reamin glued to the ground. Is a niner a little more 'exciting' or just more of the same??? BTW i'm about 5'10.

I really like mine, i'm running a One9 fameset, the Niners will be stiffer than the KM if you go for the Alu or Scandium. Steel one gets good reviews as weel though. Flys in the singletrack, capable downhill and generally bloody good fun.
Leaving the ground wise all 29ers seem hardwork to me, i find it carries so much speed i pump everything.

Raced mine XC and Enduro and will be racing Mayhem on it Solo. I run a medium frame, i'm 5'8 with a 30in leg. I've got a long back though and like a longer top tube on my SS.

Way better than my old Trek 69er

My Salsa Mamasita leaves the ground with aplomb.

Bear in mind that all 29ers (at least all that Ive ridden, and I own 2 and have ridden many more) end up with a larger gyroscopic effect from spinning wheels.
I.e. They want to stay upright.

I think this is a large part of the so called 'unresponsiveness' that people refer to. Personally I got used to it after 1 ride and never looked back – I love my 29ers.
I'm 6'2" though. Havent seen very many people less than 6' on them

Got a SIR9, it's different to my Zesty in how quickly it seems to respond for sure ie. slower, but I still take it the same places. It's hard to explain, and as the SIR9 is also SS direct comparison is difficult.

Despite feeling slower handling, it's the quickest of 5 or 6 bikes I've ridden round the same 17 mile loop.

I enjoy having 26 and 29 inch bikes, geared and SS and not having to choose between them!!

really impressed with my Air9 and carbon fork – quicker than anything I've owned before, comfy, a great fit and amazing on climbs – a big +ve difference over any 26er Ive owned.

But WAY too expensive in terms of material value …

never had karate monkey but i have 2 niners. they handle far quicker than my 1st 29er, which was a fisher rig. the sir9 is easy to jump around on when i have it set up right. my air9 has a shorter fork/longer stem and isn't quite so manouvreable.

Had my first ride my new Kona Kula 2-9 tonight, SS set up with rigid forks weighing in total 20.4lb, FANTASTIC.

Not much difference overall to my Curtis whish is also SS rigid, apart from it rolls choppy roots a bit better.

All to do with how you set it up, and how you want it to react.

The newer 29ers are different from the old ones. Much quicker steering.