I had a S2 Classic before my S3 and for its time, found it to be a step above in usability and style. It is borderline small for a guy's wrist but on the flip side is very comfortable to wear (though I believe the normal S2 is bigger than the S2 Classic).
However compared to the S3, the S2 did stutter more in transitions and I recall battery life being more than fine for a day but noticeably less than the S3 which I only have to charge every 3 days. Samsung Pay never worked well on my S2 either but this is when it was still in Beta so I'm pretty confident it should work the same as the S3 now (which is excellent).
At the right price I think it's a good buy as long as you're pro-smaller watch and you're OK charging it daily.