Hmm, I stopped playing it a while back. You can get to the top tanks without paying a cent of real money, but you are in for one heck of a grind. Much like Warthunder, World of Tanks is made by a Russian company, and Soviet equipment always seems to be better than other nations (even Chinese vehicles which were actually purchased from the Soviets, such as the IS-2). This could have changed though; it's been several months since I uninstalled it. I would suggest picking one nation and sticking to it though; the credits you earn will go a lot farther that way. When I did quit, the sighting system wasn't as bad as it used to be (you could have invisible tanks firing repeatedly at you, only 25m away, and you still couldn't see them); there were still issues where tanks would be invisible even after firing though.
Warthunder is the direct competitor to the WoT/WoWP line; right now the plane game is out, and the tanks are in beta. Warthunder is a lot harsher on credits and experience though; you'll need far more grinding to get credits and experience saved up, since 'free xp' in Warthunder needs to be assigned to projects with gold, unlike in WoT where you can decided what to spend it on.
