I've got a suspicion that many of the radio failures that get blamed on spektrum gear are in fact due to inadequate BEC power on ESC's if the power from the BEC fails then you have no control regardless of brand of radio gear. A stalled or faulty servo can also cause even a good BEC too shut down. A faulty servo was the cause of the only radio failure I've ever experienced with Spektrum gear.
I've no idea if this was the cause of your accidents but it may be premature to just the the conclusion that it was a Spektrum problem.
What ESC's / BEC's were you using?