The title pretty much says it all; I am wondering what are the differences between those 4 verbs.
From what I've gathered (and I haven't gathered much):
優れる is used when talking about something that excels, or is better than other things, without directly comparing them. (She is the best in her class. Classical music is better.)
勝る tends to be used with -に勝る when saying that A surpasses B in something.
秀でる means that someone excels at doing something.
抜きんでる doesn't really fit here(?) I list it because it is used in Goojisho's defninition of 優れる. Apparently it means "to surpass", "to stand out"
Since すぐれる and まさる * can * be both written with either 勝 or 優 I'd also like to know how often, if at all, you'd write 優る and 勝れる.
Are my interpretations correct?