I'd agree with 357sig. The SS reticle is not only different, it's better. The SS 1-4HD's reticle takes a little from the German #4, the NF FC-2, and your typical milled crosshair and rolls them into a single FFP design.
At 1X the SS reticle is an entirely different FOV experience than at 4X. The consistent black circle inside the thick posts and ghosted crosshairs are amazing. At 4X, it's fine mil crosshair is well suited for precision. Beyond that, the turrets are also 0.1 mil, which gets you some real precise adjustments if holdovers aren't your thing. Illumination brightness is comparable between the two, but when the background is too bright or complicated, the SS again provides a better reticle as it's "perimeter" circle and posts are more bold & prominent than what the PST offers. Different reticle? Yes. Better reticle? Yes. Worth an extra $300? Depends!
My preference is primarily over the reticle's advantages. The construction and durability has yet to be proven for either option discussed here. So until someone wants to drop the coin on abusing several options ranging from $500-$2500....everything about these optic's durability is speculative at best. Still, having owned and handled alot of scopes over the years, I think the SS's construction is right up there with scopes double it's price. It's a solid optic. I have a SS review thread on AR15.com, Snipershide, and Opticstalk. Someone had recently dropped their scope onto a concrete bench and marred the objective. It prompted some discussion so I contacted SWFA for some info on the tube's construction. SWFA is raking in some details for us and will chime in soon. I'm curious to know myself. For perspective, Nightforce, SS, and Vortex all machine their scopes from solid bar stock 6061-T6 aircraft-grade aluminum alloy. Only construction stat that is interesting would be wall thickness.
Anyway, I'm rambling. No disrespect to the PST. At all. At $500, the Viper PST is a great scope. If the reticle at 1X works well for you, then it's an incredible option. Besides, one would never utilize holdovers and turrets below 4X anyway, so the SFP design is fine in that regard. I also really like the PST's incorporation of fiber optics and ergonomics of it's occular/magnification adjustments. The CRS shims are interesting, but they seem to work. I haven't spent a lot of time thinking about it - but I do find it interesting that Vortex has both a PST and Razor line in their 1-4. Why is that? The SS bridges the two with one option. Not sure what that means, but it's an interesting talking point if one is to compare two brands.
These are just my 2 cents mind you. Either way with either option, you'll have a fine low power variable optic for your AR. What the recent inclusion of the SS and PST have done to the low power variable scene...is create a general purpose optic capable of both ranging and CQB. Apples to apples, I just think the SS's magic happens at 1X, which in my view puts it ahead of the PST. Performance at 1X is important, otherwise, why go with a 1-4 at all?
Still, we're fortunate in this industry to be able to choose from so many great options. Have a great weekend all