Well, everyone's eyes are different, so some folks will think it's better, some will think it's worse, and some will SAY the PST is better simply because it costs more, and they feel the need to validate their spent money. It is what it is. I used to sell optics back in the day, and we sold everything from Tasco to NF to Swaro, Zeiss, Kahles, and S&B. I've even shot through a few Hensoldt scopes before (not mine). I've spent tons of time selling, mounting, sighting-in, and zeroing and shooting through these brands back then. And customers ranged from podunk hunters all the way up to true optics snobs, SF snipers, ritzy lawyers and doctors, and some who were just snobs in general. LOL
I've seen it all. I've seen people who thought every scope under $2,500 (probably closer to $3,500 today) was trash, and I've seen folks try to justify their Leupold VX2 against a Zeiss simply because they couldn't afford the Zeiss, so they talked shit about it. It's childish, and low-IQ, but there's lots of those folks out there.
And based on all my experience, I've discovered some very unpopular truths and developed some very unpopular personal opinions about alpha-tier optics that most folks don't like. And I'll keep those to myself for this thread so not to derail it.
I've only experienced comparing a couple of Arken EP5's, and only one PST Gen2 5-25x50 that I got to look through at the range helping a guy sight his rifle in. IMO (thought my eyes), the glass of the EP5 was nearly identical, but I think it was slightly brighter. Which I think is partly due to the 34mm tube of the Arken vs. the 30mm tube of the PST Gen2. Also, the ED glass is very clear with minimal CA. The PST had pretty good glass, but it had nearly the same CA and clarity as the EP5. The owner of the PST Gen2 looked through it and said, "Damn! I wished I'd seen one of these before buying the Vortex, I could have saved some money!" So, I guess his eyes were similar to mine?