As addictive as smoking is, I found shooting it to be way more addictive. To the point where it's very easy to just decide to stay by yourself and keep shooting. I (fortunately) have not had any consistent good powder available and I don't go searching. I had an amazing cocaine hookup years ago, where I discovered what good coke was actually like, and I would love to shoot something that good. The coke I have shot was decent. Like you say though, it can get real very quickly. I can remember one time in particular where I was worried I had overdone and that my heart would give out or I'd have a stroke or something.
Edit: I really wouldn't recommend shooting any drug unless you already had experience with it. When you're shooting it can be very easy to over do, especially if you have a lower tolerance. Also, as bad as a partial miss is with dope, I've heard that it's a lot more damaging if that happens with coke. Meaning you have to be that much more careful when doing it.