The JMZClassic Win rate in Silver is ridiculously high 65-70% at least.
In Gold it's still pretty good I'd say around 50-60%.
In Plat probably 40-50%.
Most problems for me is against Mono or Duo rush decks when I get a bad starting draw, I still lose versus stall decks and control decks but only if I get horrible draws or the AI gets godly ones.
Haven't kept track of my stats though will try to remember to do so now.
Oh yeah I use the Crusader/Pulverizer version