As long as my experimentation with IV heroin is done and I never go back to that shit again, I don't regret going from smoking (how I started out, had heroin freebase) to injecting.
Smoking it yielded the most disappointing high despite what I was told by observing experienced users was correct technique with a reasonable dose of what they said was decent quality. Watching my friends get completely fucked up, I finally told them to fix me up a shot as well. The first three I had (not all in quick succession but a few days) were all much more impressive than the smoking, but still I felt as though I hadn't really "got it" - I had tried IV morphine (40mg, with just about no tolerance as well), and since heroin was supposed to be more euphoric, I wasn't satisfied with the very mild rush compared to the reasonably powerful one I got from morphine.
The fourth time they finally put quite a bit in the rig, as they were convinced by the previous attempts I would be able to handle it (and, being responsible junkies, they had naloxone on hand), and I finally felt the blissful rush I'd heard of.
That, seeing a few friends completely waste days of their life and quite a bit of money being as fucked up as I'd ever seen them made me decide to stay away from that shit. Also, I noticed by the end the doses weren't weighed out all that conservatively, so accidental overdose seemed like a matter of time if one continued using this way. Also, I got a pretty benign-looking and mild but still alarming abscess near the injection site from one of the 4 times I shot it, so I figured I'd best leave that at that.
The only times I've used H since then, I've plugged it, which was plenty powerful.