I only recently signed up for both games after getting a referral link for both of them including watching some of the Russian Badger's videos.
There are strengths and weaknesses to each game as you would expect but I have not played World of Tanks enough as yet to judge it in depth.
War Thunder might be a useful tool for "getting your eye in" as the rounds tend to go a lot quicker. I am already getting sick of the same missions though.
I did sign up with the referral from the Russian Badger but felt a bit meh with the T-127 and decided on trying out the Leichttraktor instead and a few other scrublord tanks.
I did notice the different type of shells and decided to try out a few of the high velocity shells that can pierce 78mm and got 4 kills in the one round in the Leichttraktor and a medal for doing more damage than the HP of my tank.
I will see how I go with it as I am not sure I have enough time for both games. I ended up selling the T-127 as I like the level one tanks so far except for the Swedish one which is useless.