What I would "go with", rather, are replies in the vein of what AJS914, GonaSovereign, c50Jim, and MJB have posted...in other words replies with actual, useful information.
My highly subjective 20 cents worth for indeed what it is worth..........
I am a steady paced comfort seeking rider ie) not part of the go fast set at all.
I rode a C50 2010 model for 4 or so years - the last of the C50's made) size 52 sloping.
I rode a Z2 of a riding 'acquaintance' for maybe 20 minutes whilst he tried my C50 over a road I have ridden over maybe a hundred occasions at the time. We both had Time RXS pedals otherwise it would never had happened. I was told it was a Z2 as it had not a sticker or decal on the bike to identify it at all, just a matt black tube and lug frameset.
I remember the seat of the pants feel was that the Parlee was a much lighter, stiffer / racier proposition - quite pronounced, even startling.
My C50 had 24mm heavy CG Pave tubular tyres fitted, his Parlee had 23mm, thin skinned Schwalbe Ultremo R.1 clincher race slicks fitted. The road surface was pretty ordinary too, however, I know a stiff less compliant frame when I ride one and the Z2 was just like that. I have no idea what size the Z2 was but it was close enough for me to ride it without issue.
Yet to clap eyes on anything from Calfee........... and here in Australia I'm not likely to either.
Z2 exciting and perhaps unforgiving. C50 predictable and most forgiving.
I've also ridden an original model Wilier Cento Uno and a Ridley Helium which also felt very much more race / speed orientated than any of my Colnago frames.
Very interesting, thanks much.
This makes me wonder...given that I have my Kish ti, which is very comfortable.
I wonder if the C50 would be a bit redundant to it, even if c-f versus ti, while the Z2 might provide a snappier, stiffer, maybe more interesting difference?
That definitely is something to consider, if in fact the Parlee is generally considered stiffer than an equivalent-sized C50. I wonder how the Z2 and C50 would compare to the Kish.
I am also curious as to this: the Z2 f/f is definitely the lightest of the bunch, and yet is the oldest of the 3 c-f frames (the Kish ti is from '05). How is it that it is generally regarded as the stiffest frame of the 3? Is it due to the modulus/lay-up/stiffness goal that Parlee was aiming for, even back then; i.e. that Parlee really looked for high stiffness as a primary consideration?