None of the FTP games are free of micro-transactions - that is how they make their money. What is free is that you have the choice as to whether to spend any money on it or not. Most of the game mechanics are geared towards not having to pay to participate but they do nudge you in the direction of dropping some cash on it - and so they should as nothing is free these days.
Aside from one month of premium, I played WoT free for about 4 months and had a blast. I found myself competitive and easily able to turn wallet warriors tanks into wrecks. Grinding can be slow with the reduced credits earned but that is a minor detail if you are enjoying running around in tanks.
TBH, a game like SW:TOR will have you spending the same amount to play over the same period as a game like WoT (or LoTR, or Conan, etc). The beauty of the FTP model is that you can pick it up and if it grabs you, throw some cash at it, whereas a buy then play means you have to play to recoup any value.