I have the Pardini including the 32 long, and 32 ACP conversions, as well as two Walther GSPs, both 22& 32. Both are excellent, but quite different.
The GSP is a bit heavier than the SP. and more nose heavy as well. My GSP with a reflex dot sight and no magazine is 44.5 oz. My SP, identically eqipped is 29.5 oz. The SP has 3 weights which can be removed from the barrel shroud to slightly adjust the weight and feel. I have all 3 in mine.
The GSP has a much steeper (upright) grip angle, closer to a 1911 for example, than the SP. There are custom grips which can make the SP steeper however. Originally I found the SP grip angle too raked, but now like it better.
Both have excellent two stage triggers.
Both have conversions to 32 S&W long, the SP also offers a 32 ACP conversion.
The SP is perhaps the easiest gun there is re: field stripping. One screw in the front,of the shroud. GSP is a bit more fiddley.
The SP is only available with 5 shot magazines, the GSP has both 5 and 10 round mags available.
If you are considering used, the GSP has been around forever, are much easier to find, and less expensive.
Both have excellent support, Pardini USA, and Earl’s Repair or Champions for the GSP.
Both are still in production, so parts are available.
Both will shoot under an inch at 50 yards in my Ransom Rest, using good ammo.
I love both, but prefer the Pardini if I could only have one.