[bodywerks]

I think that is a misleading statement. 72Mhz has a hard time getting a signal through carbon fiber, too. Glider guys with 100% CF airframes have to run their antennas outside the fuse to get sufficient performance.
I saw the Xlink operate with the receiver covered by a cast iron sink, so I would say that "can't pass through metal" might not be entirely true.
2.4 passes through fuel tanks just dandy, even full of fuel. Now, if you fill it with water, that's a different story - but why would you do that?
I have deliberately put a person in between myself and my plane to test that theory and maintained full control. Others have done the same with the same results.
I never tried trees, but why would I need to? Besides, all my planes are made of wood (just like trees) and the 2.4 receiver is inside it and has been working fine.

The only honest fault I have seen, and experienced, is the looooooong reboot time in the event of a receiver power drop/loss (Spektrum's deal). I have learned not to trust an ESC's BEC to four high-powered micro servos on a 3 pound plane - simple as that.