With the meta full of pirates and Questxarrs I have managed two things with this deck:
- reach legendary with winratio of ca. 80% from D5 and
- complete "On A Roll!" achievement (win 12 games in a row)
Since I am not an epic writer, here's short guide to mulligan.
vs. Questline Decks: always keep Dirty Rat and try to preserve it for the questline reward
Good luck with the deck!