The OP requests an honest assessment of comparison between the Gibson ES-335 and Epiphone ES-335 Pro. OK...here goes.
I've been wanting an ES-335 for some time, and a responsible buying decision required me to compare both Gibson and Epiphone ES-335s. The thing I care most about is the sound. Of course, playability and quality of workmanship are important, but I already knew that the Epiphone guitars coming out of Gibson's China factory these days are superbly built and can be set up to be eminently playable. I own an Epiphone Les Paul PlusTop Pro, and it's a fine instrument...easily worth many times what I paid for it.
So, I set up an appointment at a local guitar shop to do an A-B-C comparison of three guitars last week; one of them was an Epiphone ES-335 Pro. The other two were Gibson 2018 ES-335s—one a Traditional Antique Cherry, and the other a Figured Aquamarine.
I started with the Epiphone, running it through each and both pickups, with different tone and volume settings, clean and using preamp overdrive, in full humbucker mode and coil splitting (single coil) mode. As expected, the range of sounds is impressive. It's a beautifully made guitar, and a great value.
Then I plugged in the Aquamarine ES-335.
As soon as I started to play, I involuntarily exclaimed, "OHMYGAWD!" A guy who was standing nearby cracked up and said, "Big difference, huh? Kinda like apples and oranges?"
I replied, "Actually, it's more like elephants and amoebas." There's simply no comparison in the tone, the sustain, the (dare I say it?) thickness and richness of the sound of the Gibson. I'll spare y'all any additional undefinable and utterly subjective guitar blather about "shimmer", "sparkle", and "warmth". It's enough to say it sounded a whole lot better.
Then I plugged in the Traditional Cherry...and I was blown away. As good as the Aquamarine was, the Cherry just did it for me — the tone, the feel, the way it sounded acoustically, its responsiveness on leads, strumming, and finger picking. Both guitars have MHS pickups, of course, but the pickups on the Cherry were much better matched, and gave exactly the kind of sound I hoped for.
It's no secret that two "identical" guitars can actually sound and feel very different to someone who's sensitive to those differences. That's what happened when I picked up the Cherry. I knew right away, "This is the one!"
I walked out of there with my very first ES-335 — a 2018 Traditional Antique Cherry, and it's a keeper.
I won't participate in a pointless argument about whether the differences in sound (or other qualities) between the Gibson and the Epiphone are worth the difference in price. Of course I think they're worth the price difference; otherwise I wouldn't have spent so much more to get the Gibson. But I make no representations that my subjective preferences apply to anyone else. Talking about it is useless. My best advice is to go play the guitars, and get the one you like best. It ain't rocket surgery.
The OP asked for my opinion, and there it is. I expect that everyone else must do their own homework, their own due diligence, and make their own choices based on their own subjective valuations. All I can say is that, for me, there is a huge difference between the Gibson and the Epiphone, and that difference is worth every penny. YMMV.
