@Jason its not. Its top tier USF tank destroyer, its supposed to effectively fight heaviest axis armor, because if it won't, then nothing will, there is nothing above it. It performs fine for a glass cannon it is.
Which is why some people have suggested giving OKW a Self Propelled Artillery piece that costs fuel similar to a Priest (Hummel or Wespe comes to mind!) so you couldn't camp with it and it would cost fuel so you couldn't spam it.