1500 gold is a lot, but to me the KV-13 is worth every bit of that, if not even more.
I have just a hair under 200 battles in it at only a 57% winrate, but that's not the tanks fault! Rather the fault is mine as transitioning from heavies to mediums has not been the least bit easy for me. (same with me learning to play non-turreted TDs),
But the KV-13 is an awesome, much overlooked tank that I have no plans on selling.
Here are screenshots from my first battle in it since the update, taken just a few minutes ago... I was the only tier VII tank in a tier 8 battle.