As far as I know, Senderos are only chambered in long action cartridges, .25-06, 7mm Rem. mag, .300 Win. mag. The PSS can be either, short or long action, although in my parts at least .308s are what you'll most commonly find in stock at local dealers. I think the only magnum cartridges you can get in a PSS is the 7mm Rem, .300 WM, and another one of the big magnums, .300 or .338 something. .223 caliber PSS' had 1:9 twist barrels, everything else was 1:12.
Senderos/VS' don't have the wide fore end or the more pistol grip-ish stock that the PSS does. At one point, you could get a PSS with a 5R barrel, although I'm not exactly sure what the hype was behind the 5R. My non-5R barrelled .308 VS makes nice ragged one hole groups when I do my part, and I couldn't hit the broadside of a barn from the inside.