I too, like to have a separate transmitter for each tank and that's one of the reasons I like the I6 so much. $50 each and additional receivers are easy to get and cheap. I know the Tamiya fans like these radios, but to me it seems kind of foolish to spend $150 on a Tamiya radio when I can get three I6 transmitters for that price that are actually better radios with more functions.
And for the guy using the FlySky 10 Channel, I also have the I-10 and it's pretty much the finest radio I have ever owned. I haven't tried the taranis, partly because the I-10 has been so easy for me to use I don't see any reason to get any other radio.