The SP offers me more foot support, about 95% of the eddy thrust with a frog kick and about 140% more in a flutter kick. Leg fatigue is about 30% less with the SP.
overall fin is very similar in size
The SP GS has some tip flex that has a lot to do with the ease of use in a flutter kick and a bit of snap at the end of the stroke. In the frog kick it has a slight tip flex. I don’t know how they will hold up overall but so fat no complaints. A good fit and pretty amazing performance for such a light fin, price is also not nuts, I have a second pair in yellow coming.