According to Trump, putricide has the worst winrate of all cards in the deck. He seems to be a natural fit for secret hunter, but he allegedly underperforms. And I believe that since he is clunky. Best support for that is the advice to use him lategame with two secrets. Against control, that won't help much, against aggro, you usually cannot wait that long to play your cards.
I use Shaw and he is just great. He has at least synergy with Wellstone and flanking strike and all other minions you play (From DK Rexxar, animal companion, whatever). And he has 6 live when played on curve.
If you have putricide, well, play him. If you have to craft either, I am sure that Shaw is better.