Someone with henna hair dye experience!?

ok, i want to know everything about henna hair dye. does the natural henna (not the tinted henna, because that kind has heavy metals in it) really make your hair bright red? and if it does, how long does that last for, because i thought it eventually faded out into a dark brown color with a red-ish sheen? and is it really as good for your hair as it proclaims? (making it shinier, and coating it with a protective protein?) and any other tips about getting your hair professionally dyed with henna? cheers!