I don't think mental illness is cool at all. That's like asking is it cooler to have cancer or aids...hmm....??
The only reason I ever "wanted" to have it was because I wanted some explanation for being so screwed up, and at times I think it would be easier to blame it on illness than just blaming it on myself. But I don't really want a mental illness. That would suck. I just want to be more normal and it would be nice to have some kind of explanation for the things that I do. But when I really think about it, I don't think there is a good explanation, and even if there was, I don't see how it could really help, because I'm gonna dislike myself reguardless of what's wrong with me or what I can or can't help.