The EP in my sig was done entirely by me.
I'm a pretty firm believer that you won't get the best product doing everything yourself. I just doesn't work that way. But it is fun and you do learn a lot. Its something I'd recommend as a side project, but not so much as a full on project that you expect to take off and be the best that it can be.
One thing it does is round you out as far as what is involved with making a record start to finish. And I mean everything from the first chord and lyric, to the gear, to the mix, the master, the manufacturing (burning discs and printing crappy covers
) and trying to sell it on top of that. It can be a pain in the ass doing all this but you'll be better off having done it once.