I thought it was a bust too. Until I unlocked the 107 mm Zis-24 exclusive KV-4 tier 9 gun. Boy was it fantastic. Starting to become my favorite tank of all time (granted I haven't played even a third of all the tanks in wot). Trying to three mark it, only had 30 battles in it but based on my battles so far its possible. Pros: Reliable gun and pen at tier 8, able to face higher tiers no problem, big baddy in brawling (sidescraping dishes out atleast 2k in dmg blocked), and I've noticed that since its so tall it can spot enemies considerably at times. Cons: slow (very slow) and high profile, but thats about it. Give me your reasons for not playing the tank, I would like to hear it out.
Edit: I'm not too good at the game, I guess KV-4 is pretty noob friendly. Only two 2 marked tanks so far, hoping this will be my third 2 mark tank and my first 3 mark. I have 4.5k battles and 4580 PR and 50.24% WR.