S/O dying hair...has anyone used henna?

miababy

I need to color my hair bad!  I'm planning on trying henna.  I haven't done it yet, b/c I couldn't stand any smells with my m/s.  Now that it is about cleared up, I really need to do something about this mop!  I've never tried it before and I must admit that I'm a bit nervous!  I colored my hair several times when I was pregnant with DD, but the color never held and it always looked really drab.  I've heard henna does a better job, but I'm still a bit scared about the results!  Oh, and I got the brunette/reddish color instead of the full on red.  Anyone else ever henna'd?  Any tips?