Both are fine and it really just comes down to what you like better. Simply put, WoT (and Blitz) is an arcade centered game while WT takes a more realistic approach. War thunder has been around a bit longer, though not the tanks, but they were roughly started at the same time (and far more time is put into each individual vehicle) and lots of research is needed before they finish a tank to add. Armor and models are far more detailed, defeating a vehicle requires either wiping the crew out or setting off the ammo, every tank moves differently (based on weight, what it is driving on, horsepower output from the engine, length of the tank, etc), different ammo has very different post penetration affect (APHE style will do far more damage to multiple components then say solid shot). War Thunder goes for the more realistic gameplay.

WoT and Blitz are very arcade gameplay style with a health point system, lots of paper and prototype vehicles that saw very small or no production at all, far different spotting and aiming system, a more basic movement system, etc.

World of tanks blitz vs war thunder