Before My old JR died I had purchased a Spectrum module and RX to convert it to 2.4. It was the "old" DSM2? standard. I never had a "brownout" or other issue with the system. I even used one of the HK Orange RX's with it. Never had a problem with it as a 72 mhz system either.
IMO it is the same with 2.4 as with the 72 mhz systems. Most crashes are blamed on the radio and not where the blame really lies, with the pilot. After all, we pilots NEVER make a mistake.... Do we?