T-10
The best Tier 9 Heavy and Medium in one go. When I played through the T-10 it was called the IS-8, and it was still an excellent tank even then. Once I was done with the grind, I kept the tank in my garage and it later received a buff, becoming the T-10. There I 3-Marked the tank, as every battle in it was a breeze.
There’s just nothing cripplingly bad about the T-10. Sure, you don’t have very good gun depression, but it’s not like some of the Chinese or Russian Mediums at 3 degrees. Your frontal armor isn’t Super Heavy level, but it’s an Assault Heavy anyway. You then get excellent DPM, punishing alpha damage, and high penetration with your 122mm main armament. Your gun handling is pretty damn solid too, allowing you to put consistent fire down on your enemies during any given engagement.
The 80-120mm of side armor allows for workable side scraping and reverse-side scraping, and the extraordinary turret armor enables hull down positioning. Finally, the mobility of the Tank is where it really comes into its own – especially considering its armor. A top speed limit of 50 km/h with solid traverse speeds, terrain resistances, and hp/t ratio makes the T-10 an impressively mobile vehicle. The front-mounted turret and 15 km/h reverse speed means the T-10 excels at peak-a-booming. Overall, the vehicle is just endlessly versatile and can perform on any map you throw at it.