According to one of the guys at on one, the test bike came back with 20 psi in the tyres and set up badly which probably accounts for the review!
I’m also 5’10” and a few months back whittled the choice down to a 18″ c456 and a medium (17.5″) cotic BFe, having previously owned a simple I went with the BFe as I knew I already liked the geometry. run it with a 120-150mm rev and its happy across that range.
But to be honest I would have been happy with either frame so try and demo one or make a choice and have fun riding it.