I'm not too familiar with the MSI mobo, but the differences between the Maximus and the Prime that was suggested earlier are:
Maximus supports 4133MHz RAM, Prime supports 3866MHz
Maximus has 2 more PCIe slots, one more 3.0 and one more 2.0
Maximus has a few more USB ports (all USB 3.0 IIRC)
Maximus is slightly smaller (physically)
Maximus supports 6 fans, 3 more than the Prime
Maximus supports THREE GPU's, Prime supports two
If you really need those extra features, sure, get the Maximus. Otherwise, save yourself $100 bucks and get the Prime.
That's my $0.02 after having recently built a new PC. Have fun researching though! It's honestly one of the funnest parts of building IMO.