Pebax vs PU

Looking at all the new touring boots I noticed that a lot of the top of the line ($$$) boots are made out of PU (Poly-Urethane). Most of my ski boots are made out of pebax. So that there is (supposedly) less difference in boot rigidity in varying temps of hot or cold.
I guess I don't want a boot that is rated as stiff that turns into chewing gum in the spring.
Or even a boot that won't flex in cold temps.
What is your take on the PU boots and temp variations compared to the stiffness of the boot?
Right now my Megas (pebax) are on the end of a rope. I think that they are too soft and I rely on to much skill rather than having a boot to compliment the skill. But the PU boots make me question their effective use in temp swings. Snow conditions are enough to deal with day to day rather than a moody boot due to temp swings.

I rely on to much skill

Rub it in why don't you. :

Snow conditions are enough to deal with day to day rather than a moody boot due to temp swings.

Thank you for providing the perfect excuse when I fall and have a gaper day this coming season.
I shall reply... "It's that time of the month and my boots are moody today"

I'll be interested to hear the result of your question.
My own feling is that the temp swings here( PNW) in a normal winter season ( excluding winter versus late spring touring) are not enough to effect the stiffness to the degree that I'd notice it much.

I've been under the impression that polyurethane was more susceptible to temperature fluctuation than Pebax.

Sounds like you need to go CARBON FIBER.

pebax has less temperature variation the PU, but is generally softer, it is also lighter. Most Alpine boots are PU, most AT boots are pebax, mega-rides are soft boots just buy something stiffer. Be warned the new garmonts (radium) are a lot narrower than your megas

My Zzero 3s are pebax and my Zzero 4s are PU; I find the PU to be more comfortable and more flexible than the Pebax; the 4s are slightly heavier than the 3s and the extra buckle is kind of a hassle, but I find myself using the 4s more.