Eventually destroyed (almost - I did glue it back together although it hasn't flown since) my GWS Big Moth - some gory details here:
http://www.oz********.com/2007/01/big-crash.html
http://www.oz********.com/2007/01/interference.html
http://www.oz********.com/2007/01/in...continued.html
With the benefit of hindsight and a little more experience I think the fundamental problem is that the EF Receiver will not do a good job with 4 channel setups. 3 channels seems to be okay.