s-8 is good but there almost exactly the same as the s-3.
The only difference is less than 2 grams of weight, price ($10 - $20), and that the bearings on s-3 are black oxide, and the s-8's are stainless steal.
Supposedly the s-8's are meant to be a tiny un noticeably smoother and better.
But if your looking to save a bit of dosh s-3's are dope.