If I had to pick one and only one, and they were both NIB, I would take the Python.
Why, because it's the best shooting .357 DA revolver made. In my, not so humble opinion.

To be honest, I'd rather have the Python AND the 27.
Throw in a Dan Wesson, too. I like them a lot.
Since I can't afford a Python, I'm more likely to get a 27.
Although a tuned 586 would be a closer competitor to a Python, since it doesn't weigh a metric ton.

Hell, I just want all of them.
I'm a lifelong Colt fan.
But, I'm also a Charter Arms, Dan Wesson, Ruger, Astra, Smith & Wesson, Taurus, Freedom Arms, and Rossi revolver fan.
I realized I didn't have to like one brand OR the other. I can like them all, except Block.
I have GM, Mopar, Ford, and Honda vehicles.
I don't like to limit myself.

BTW, my buddy had a Llama Comanche 3 .357 that was a sweet shooter. He sold it and regretted it. I wish I'd been in a position to have bought it from him.

Now, for an everyday .357, I'd love to have my old 4" Ruger Speed Six back. The, unknown to me, previous owner had an action job done on it and it was one helluva good shooter.
It had a better/smoother trigger than any other revolver I've ever shot.
Not quite sure how that was accomplished.
Must have been a damn good gunsmith. Must have cost a pretty penny.
I was stupid to let it go, but needed the money for car repairs.

Aesthetics are definitely a subjective thing. I like the looks of Colts, but never liked the looks of an adjustable sight K frame.
Always preferred the 13 to the 19.
Not like that would stop me from buying a 19, but target sights on a combat revolver look silly to me.

On the opposite side of the coin, I don't like the look of fixed sight Ruger Single Sixes, unless it's the 4-5/8" .32 Mag.

See? Very subjective.

But, I'm right and you're all wrong.
Come over to my way of thinking or stop breathing my air, dammit!!
Just kidding, of course.

Buy what you like and shoot the hell out of it.

BTW, the ONLY Colt DA I've ever shot or handled that had timing problems or loose lockup was an old Numrich-converted New Service in .357 Mag. And, to be honest, that gun was designed for and metallurgically suited for 15,000 psi, not 35,000 psi+ loads.
Can't blame the gun.
Much like K and N frames shooting loose from a steady diet of full power magnum loads.
Can't blame the gun for wearing out, due to abuse.