I am a bit geriatric (that's when you hit 40, right
?), and have owned, at the following order:
Giant carbon something vintage 2000, Santa cruz roadster, Look kg381i, cervelo soloist alu, cerveloR25, Cervelo R3 and now a Parlee Z4.
I have also ridden quite a bit Look585 and 595Ultra (not mine).
I do not race, and weigh ~85Kg as of today. riding a medium frame. i appreciate a stiff bike with a comfortable ride.
I would say that comparing the Parlee (Z4) to the Cervelo R3 (known as a very stiff / racy bike), the Parlee is just as stiff (i cannot tell a difference in stiffness), yet it is much, much more comfortable and has a much more refined ride.
It built just as light as the cervelo (maybe 100gr more, hitting 7.3Kg with record10, neutron clinchers, Ea70 stem/HBar, Ec90 post, LookPP396 pedals and Selle something seat. no weenie parts on that bike).
If i compare the Look595Ultra to the Z4 than i would say the 595Ultra is a tiny bit stiffer (totally neglect-able) and maybe has a bit more refined ride.
Only bike i would consider swapping the Z4 for is the Look595 Origin, or a look585.
This is probably not driven by the ride characteristics, rather is driven by the fact that i really want a look, it is one of the sexiest bikes on the planet in my eyes (
), and has a ride that is similar/a tiny bit more refined than the Z4.
I do not race any more, but (i believe) i do know how to appreciate a bike; you probably will never regret getting a Z4.
Take the Z4.
If you still hesitate, picking a 585Ultra/595 is a darn good idea as well.