That's bullshit.
a little hint for the newcomers: A DX6i is all you'll ever need, or get a DX7 if you can get a good deal from Sabe.
You don't need any of the bling, and it won't make you a better pilot.
If you some day want buy Rave 90, JR Vibe, Sylphide, Hirobo Eagle SWM or SDX... you can't use 140 deg CCPM. DX6 support only 120 deg CCPM. Unfortunately DX7 also knows only 120 deg CCPM-swashplate. Electric Swash-ring is also excelent feature, but if I understand right, DX6 and DX7 doesn't include that functionality. Let's look channel count. DX6 is fine realy basic setup. Aileron, Elevator, Pitch, Rudder, Thorttle and Gyro gain needs 6 channel. If you use nitro engine and you want remote needle, you need one channel more, then DX7 be enough. But if you use governor what needs one channel more, you have to buy DX8. May be you fly scale models with extra features like working landing gears, lights or jet autostart, then you need more extra channels.
In F3C pilots use many curved mixes in radio, like aileron -> elevator, Pitch -> elevator. DX6 and DX7 radio doesn't have any curved mixer. So if you want get podium place in finnish F3C competitions, you need better transmitter or you have to own more than natural talent for flying.
If some thing is enough for you, it's wrong to say same enough for everyone. DX6 is good radio and it enough many of pilots for their lifetime. But it still wrong to say, that enough for everyone.
Finally, in my text is probably many grammatical errors. I'm not good in english, but I hope everybody understand my message.
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Timo