I'd be concerned about age. The CLP430 was sold from 2011 to 2014. So it's at least five years old.
I wonder about the "flawless condition". There isn't much on the outside of a piano that can go wrong. It's what's inside that counts, and you can't see any of that.
When new it sold in the US for around $2000, perhaps a bit more. You say that it's priced about the same as a new FP30 with stand. That's $700, yes? I think you might try to get the CLP430 for less, if possible.
But on balance I'd lean toward the FP30. Brand new. With warranty. Not as nice looking as the CLP430. But it's new. With warranty.
One thing I've omitted ...
Have you tried both pianos? How does the feel compare? How does the sound compare?
Aside from condition ... I think those are the most important items.
I have a very hard decision to make am buying my first good piano because what I was learning on was not close to an acoustic piano at all. Anyways I saw a used Yamaha clp-430 in a very flawless condition at the price of the (Roland FP-30 with stand and pedals), so I was wondering which key action do you guys recommend: the GH3 or PHA4 standard. Thanks for your time and help.
Btw is the clp430 even still valuable or worth it?!!