It's the best TD in the game barring the heavy ones like the Jadgtiger and Elefant. All it needs fixing is a increase in ROF and a sharp decrease in damage.
Actually, JP4 is out of stock units.
Above average sight range that gets even better with vet without slowing down the vehicle itself, really decent armor, good rof, excellent penetration, great vet ability, awesome scaling, can arrive extremely early.
There is literally no downside to it and no reason not to get it if there wasn't a panther that also can fend off infantry and obers in T4.