Not sure an iO is a complete comparison to an Altitude but the geometry isn’t miles apart and I’ve actually got a bouncy fork on mine now.
I can second James’s comments – it’s definitely a bike that rewards a firm hand – very chuckable, I find myself hopping and popping this thing more than anything else I’ve owned.
It feels quite soft at the backend, not overly so as it still feels nice and stiff under power, but in terms of hit taking it’s very forgiving. Since fitting a fork, I’m able to hold my own with full sussers as it’s light enough to just jump the nasties and when you do go wrong it’s got that classic steel forgiving nature.
There’s something Joe Murray Kona about it. Long, low, light, forgiving and fast!