The sturmtiger isn't unless lol, the sturmtiger before patch was OP and could fire it from max range without even being seen by your opponents. You could max range wipe tanks in the fog of war out of their LOS with ease and is considered unfair. post patch the sturmtiger is harder to use due the its new short range of 40 which was needed to bring it inline with all allied tanks. The St is still a useful tank saying its unless before the patch is a utter joke LUL.
https://youtu.be/sgbu_JKtxfA?t=54m5s that youtube link is to a game cast where i got the ST to vet 5, it took longer due to the map and its new nerfs. buts its still possible to use it if opponent has brain delay Kappa