One difference between the M4M and M4M nextgen styles is that that you don't have to choose one of the wide variety of likes from a pull down menu under "Rate"; instead they arrayed in a horizontal row. The default text font also seems darker (for me, easier to read) and there's less white space on the page (which means less scrolling - and concommittent risk of RSI - for me). I have no objection to multiple skins, but I think I'm going to choose the M4M style for myself if it sticks around ...