For the people who got far in the beta, hows this for a plan, level up a russian tank whilest leveling up a german tank destroyer. I hear russian tanks are overpowered. Good idea? How are german TD's?
Russian tanks OP? No, just easier to drive effectively imo, give or take a few armour bugs.
The German TD's are quite good. Until you hit the Ferdiand, they are reasonably mobile with good guns and front armour for their tier. Once you reach the Ferdinand, they are slow and ponderous but very heavily armoured frontally, give or take the armour bugs/exceptions.
I do recommend picking two lines you want to progress and heading down that road. It allows you to switch out when one dies early in battle and progress the other.
Personally, after getting the Tier 8 Russian TD and Tier 7 German TD in CBT, I'd recommend the Russian TD's. Just so much fun with a massive gun, sneaking around and popping a round off at anyone you see. The upper end are slightly more mobile, weaker armour but much bigger gun (better penetration and damage I believe).
As for mediums, I had a T-44 and liked it with 100% crew and fully tricked out. The T-54 is allegedly Godlike but I feel that the Panther II is better. Well armoured, less mobile and packs a very nice gun which has penetration, damage and refire rate. The Pershing wasn't used much when I was around so I can't comment too much. People didn't seem to be too impressed.