RE: What's the benefit of 2.4ghz over 72mhz?
As Mike said, no issues with frequency control.
Also 2.4 operates above the frequencies generated by most sources of interference like rubbing metal and electronic ignitions so its much more resistant to outside interference sources than 72 mhz radios.
If you go to events or fly at a big field with a lot of people (we have 200+ members) then it's a no-brainer.
But like he said, if you're starting out today it's the way to go.