Looks like the M2N-E has on board firewire, which the other doesn't. If you don't need the SLI and onbard firewire, you'd be better off with something like this, which has the 570 rather than the 500 chipset http://www.newegg.com/Product/Product.aspx?Item=N82E16813131022
M2N4 SLI is based on NFORCE 4
M2N-E SLI is based on NFORCE 500 ,i say go for M2N-E SLI , and also i agree with g-paw , if u dont need SLI , go with M2N-E
M2N4 SLI is based on NFORCE 4
M2N-E SLI is based on NFORCE 500 ,i say go for M2N-E SLI , and also i agree with g-paw , if u dont need SLI , go with M2N-E