Last night I gave it a (literal) shakedown run up and down wessenden valley.
It rides pretty nicely, and the heavy wheels, large frame and very XC-oriented geometry give it a very planted feel, but it is generally unwilling to get any significant air (which is fine, that's now what it's meant for). Front-brake only riding takes a little getting used to, especially on steep, muddy descents.
Just finding the little niggles (already raised the bar up, was too low, now found that the bar itself needed rotating slightly to remove slight downsweep) and loose bits.
The simplicity of it is appealing, you can just pick it up and ride it, there's nothing to go wrong. It's also pretty quiet; we get used to the noise of forks, shocks, chainslap, derailleurs, etc. Singlespeeds just have the noise of the tyres really, and a little chainline noise (but much less than a gearie, and no chain slap because the tension won't allow the chain to hit the chainstay).
All I want to do with it now is rebuild the front wheel with XM317 and DT revolutions (saving about 300-400g over the current front wheel, keeping the same hub), and build a new rear wheel with an SS hub (DMR or surly probably), again on XM317 and revolutions.