as long-term silverfish user on another bot (HearthCrawler) i can tell ya Silverfish was 1 of the best A.I around there !
when HC was still alive silverfish was updated almost every day and worked well with all kind of decks (aggro,control etc..)
i saw few ppls to reach legend with it before GvG release,unfortunately i dont know alot of current bot meta success and top ranks reached.I got around 80% winrate with 1 or 2 rares and all other commons without GvG cards in hunter deck with it and then HC died and silverfish become hearthbuddy A.I.
Actually right now Silverfish is default A.I on Hearthbuddy so i think its kinda good and as a fan i will try it and post winrate % as soon as i got results.
SeasoN 8 Legend Rank reached with bot