Has anyone compare the 9mm Shield EZ and the Performance Center 9mm EZ? Is is difference worth the upgrade??

First - I do not own EZ, I'm still OK with regular M&P9
But having both in hand one day this is what I can say:

It's mostly personal preference. Is it worthy? You will have to decide by yourself.
For me personally the ONLY advantage of PC would be factory flat trigger. No other "upgrades" are for me. I don't like ported barrel nor ported slide. Even the sights are better on PC I would probably change them to Trijicon HD (which are my favorite and installed on almost all of my handguns).
PC has one downgrade comparing to regular EZ - grip safety which is made from aluminum... feels oddly and uncomfortably.

Check this video, you will find it interesting regarding your question.
S&W Performance Center Shield EZ...Better Than The Original? - YouTube
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I originally had a PC Shield 1.0, chosen over the std Shield. I liked that PC and its features though will note some ammo brands recommend not for ported use. Up to other owners if that’s important or not.
When I got my EZ Shield I no longer wanted a ported model. I like the std EZ but admit I did not try handling a PC model for any comparison. I have seen others complain about its grip safety vs the std model though.