they were selling an s5 also at a higher price of arount 400USD 2nd hand but do you think the bitcoin prices might fall to 0 with all of the negative news?
If it's working I would not mess with it on a S3. It has two very nice fan's and honestly is built tough like a tank. Just no reason to redo paste if it's working.
I personally would buy S5 direct from bitmain and not second hand unless you get a huge deal the warranty is nice to have.
And on price that really goes in speculation. Needless to say those of us who are mining obviously think it is going to be a good investment not go to zero. And honestly it would take a LOT to go to zero almost impossible. I don't foresee this happening. I think were slowly on a upswing on price. It's been a good summer.