I've now had mine to the range a few times, I wouldn't say I hate it, but I'm also not planning to run out and buy more of them.
So most of my range guns either wear a Vortex Razor 4.5-27 Gen 2, or PST 2, 5-25's. I'm not a big comp guy, I don't rely on my guns for anything other than enjoying at the range, so take my thoughts as you will.
Optics wise, it's good and bad. Resolution wise, it's quite nice, it struggles over 25x but it's better at 25x than the PST 2 is at 25x noticeably so, at 20x they are both pretty even. I tend to zero/group test at 25x so I give the nod to the XTR III being nicer at 25x for sure, and of course getting an extra 5x never hurts, but I usually don't dial to max anyway. The reticle is certainly nicer to use at 5x than the PST 2, however here again I spend almost zero time at 5x. As others have mentioned it's not great in low light, our range opens at 7am and on a cloudy day like this morning the PST 2 was noticeably brighter but both were useable. I wouldn't put either on my hunting guns so extreme low light performance is not an issue for me aside to note I was surprised it was obviously darker. I prefer the center dot of the EBR-7C, but the small crosshair worked perfectly well, and that's pretty much personal preference. I do like the locking diopter adjustment of the XTR III, and I found it quite easy to adjust. Eyebox was nice, I'd say more forgiving at 20-25x than the PST 2, but that's probably because it's not at max power. At max power I'd say they are pretty close eyebox wise.
Where the XTR III at least mine, is very disappointing is the knobs. The elevation knob has 0.05mil lash/slop, but nice solid/loud clicks, but the windage knob clicks are so light and mushy I can't dial it by feel at the range, something I'd expect to run into in a $300 scope, not a $1100 one. Removing the turret o-ring would probably help the clicks feel more solid, esp. since the turret knob really fits tight on the o-rings, but that could be compromising the sealing of the optic, it also does nothing for the elevation knob slop. I did try to "cheat" the knob and see if slop/lash impacted elevation, IE is the lash just there or is it impacting elevation, both visually and in groups I could not see a difference, but it feels "cheap". That said I could get past it, and probably never notice it shooting. I have several PST 2's and none of them have that issue, the PST clicks are not as hard and audible as the XTR III elevation knob, but much better than the XTR III windage knob, they are consistent where the XTR III windage I can barely feel behind the gun. If you always hold windage I guess it doesn't matter. I don't use the zero stop as I have it setup on a .22 and elevation/zero changes pretty significantly when testing ammo. Bottom line for me is I've never had a problem dialing a PST 2 by click feel, and on the XTR III I can't do that for windage, and even visually it's very hard to see/feel when the knob has settled in a click.
The PST 2 5-25x might be old, and folks love to pick on it, but considering they often end up on sale recently in the $700 range these days, I'd still consider it a really good deal for just a range optic. Burris would have to address the knobs before I'd consider buying another one, esp. with the reports here of people sending them back only to get the same thing back saying it's fine. If they fixed the knobs, I could see slowly swapping out some PST 2's for them. The XTR III's used to be cheaper but now seem to be settled in that $1100 range at the cheapest I could find. That's a 55% increase from a PST 2 at $700, also the cheapest price I could find currently, so it's a significant jump % wise in "best deal" pricing.