Mine is a 4-16 model but anything over 10 power it becomes very hazy regardless of the distance, call it a clarity or resolution issue ( i am not an optics guru) but I have cleaned lenses, adjusted ocular focus, parallax as well, only when I dial power down to 8 or below does it clear up. Is it something that is an occasional flaw on pst that only affects a few of us? Maybe, but I do know that once I can afford an upgrade this puppy will be finding a home elsewhere or on a rifle that I do not need 8+ mag, but does it make sense to pay for a 16 or 24 X scope and only be able to use 50 or 60% of that total magnification? No.
To those that compared PST to Swarovski, zeiss, NF, and other brands and thought that PST held up to that standard of glass, I question the standard of the comparison, I have a conquest and the pst is not even close in the top half of the mag range, maybe at 8X it might be close, maybe if there is dust on conquest lens, probably not though. I have owned a couple nxs scopes and even though I was disappointed (might be too strong of a word) in the clarity at 22X it still blew the pst at max magnification of the water.
The PST is a very well built reliable optic that serves it purpose of dialing all day long and coming back to zero without question, but it lacks the optical quality IMHO that other brands it was compared to in this thread, but hey if it has zeiss, trijicon, or atacr glass it would be a 2K optic (it's called a Razor HD) there is no free lunch on that one. I do like the Vortex no bs customer service and the razor line glass is awesome so for that reason I will be sticking with them when I upgrade just not a PST.
I understand that everyone's eyes are different and good glass to one person may be sub par to another and great for his buddy. This is for various reasons I will not claim to be an expert on but most of the time it is probably a representation of the quality of optics that person is accustomed to. The comments above are my experience and opinions, so PST lovers don't get huffy with me as I feel I gave it all the credit it is due and for what I paid it has been a relatively good optic.