I'm enjoying the T1 heavy tank now, it's still a brick, the first engine upgrade has done little for my top speed, but the acceleration is better.
Still loses massive amounts of speed when you turn, top speed is about 35kph start turning and the speed drops to about 15kph
The gun is ok, nothing amazing but not too shabby, not got the upgrade just yet, however it's not very different, bit higher rof, bit more damage, a bit more penetration.
However the thing that makes it decent is that while it looks like a brick, moves like a brick and handles like brick, it's also built like brick and can take hits and keep going.