I'm a big fan of Dr. Bronner's soaps in general. I've bought the largest one of these as refill for my little bottle already and use it often. I can see how the tea tree may irritate some sensitive skin though, my boyfriend used it and although he really likes it, he described it as "it cleans too thoroughly". I attribute his opinion to the tingly sensation of the tea tree. Other Dr. Bronner's soaps don't have the same feel.
On the other hand, I also have sensitive skin, and it does not irritate me at all. I'd like to remind people that it should be diluted, an instruction that is hard to read on the small bottle (especially since they have all sorts of other writings on the label... a little much).