The two things that are notably different are the s/n (although even the amp with the worse specs is probably past audible thresholds), and the low impedance limit explicitly stated for the second amp/lack of 4 ohm ratings. Distortion specs on the first amp are of the more forgiving @1khz variety; it's probably closer in power to the second amp under the more rigorous 20-20k type rating method. Either way, the 8 ohm power rating differences are negligible, but it looks like the second amp quite possibly has better current reserves for low impedance loads. It's impossible to say for sure.
