E:wom has about an hour or two of buggy campaign for you to play. If playing the beginning of a story is your thing I'd recommend playing that (note - you only get to play the beginning, not the middle or the end of whatever story they were going for).
As for FE, it is a far superior game but we do not yet have access to the campaign. We only have sandbox which has no specific story. Since we don't have access to the campaign in FE it is impossible to say if you are "missing" something if you don't play E:wom first. If you merely wish to enjoy a good game (and don't care about the story that much) then play FE. E:wom was terrible, FE is very good and bordering on great.
