Both should be similar in open field / line of site applications, but 2.4 penetrates walls MUCH better than 5.
There can be a lot more noise in the 2.4 band (cordless phones, Bluetooth, wireless keyboards/mice, your neighbor's routers, etc, etc, and even some non-radio type devices like microwave ovens and electric motors are more likely to pollute the 2.4 band than the 5 band).
But don't let any of that scare you, 2.4 works just fine for most folks. Barring unusual interference issues, unless you get an internet connection better than 30mbps, or start doing lan to lan transfers you are not likely to have problems or notice any difference.