Well if he does want to go down in price he can chose the second for $50 less. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It has the same GPU my laptop has (since it's a rebadged 555m) in my Lenovo Y570. The resolution of the screen is only 1366 x 768 and with an overclock I can run metro on ultra if I don't have AA cranked up without any hiccups.
Regarding #3; the Radeon HD 7670m is marginally more powerful than the nVidia GT630m. However AMD's A8-4500m is a bit weak as a CPU especially considering it is clocked at 1.9GHz. Assuming the same clockspeed, Intel CPUs are more powerful than what AMD has to offer. Therefore the performance difference from a CPU standpoint is more than the 600MHz clockspeed difference.
Having said the above, most games are dependent on the GPU rather than the CPU. So as long as the CPU is fast enough there will be no affect on performance. Crysis 2 is an example of such a game. But there are some games that are dependent on both. Skyrim is an example. Skyrim will perform a bit better on the Acer Aspire V3-571G because the Intel CPU is more powerful than the AMD A8 APU. That even though the GT 630m is marginally slower than the Radeon HD 7670m.