I've taken Bromo-Dragonfly (a confirmed part of the notorious "B1" batch that caused the deaths of an RC purveyor and others) at least 7 times, and I'm still not entirely sure how I feel about it. The first time I was quite impressed by it, by the increased energy levels, mild but unique visual, and the feeling of mentally being in a higher gear, more clever (at 350mcg). Since then I've taken it in doses of up to 600mcg, and will definitely do it again, as I'm not going to run out in this lifetime...but I think that it does have some drawbacks.
One problem is the body load. The come-up can be difficult, with nausea, restlessness, and muscle tension, which is worst in the first three hours. Even when its in full gear, there is a moderate sense of edginess. I agree with Apradavra when he describes it as a slightly toxic feeling (very similar to the tension caused by methylphenidate). This wears off after 6-8 hours, but it makes the experience much less physically comfortable than say, mushrooms. Also, one can experience what I call "dragonfly shivers" very brief bouts of shuddering (not involuntary) that seem to send a wave of tin tremors throughout your body. I have found that taking an occasional nitrous balloon, once every half hour or so, is a nice way to let off some of the tension. Cannabis can also work, and really brings out the visual qualities of BDFLY as well.
Another drawback is the absurd amount of energy it gives you (though some don't have this problem). After hour 4, I will want to go on endless walks to let off this energy, because if I'm sitting down I will get really restless and fidgety. First time I took it, I walked continuously for over 8+ hours, and when I came home I was not the least bit tired. This makes me think this would be an ideal chem for taking long hikes in the mountains, though I haven't tried that yet. Also, this energy makes falling asleep within 24+ hours of dosing impossible without a decent benzo or some opioids to calm the legs.
The biggest problem with BDFLY though, it is its lack of a "normal" psychedelic headspace. Apradavra put it very well, and I never really knew how to vocalize what I felt was missing in all my experiences until I read his post. With other psychedelics, one feels connections, and sees new relations between concepts and ideas, which generate psychedelic epiphanies. BDFLY is extremely deficient in this sense, it seems to be much more of a "surface level" psychedelic, providing interesting visuals, but always feeling as though its leading up to something bigger, and then falling short. Unlike Morning Glories or psilocybin, BDFLY trips tend to feel somewhat unfinished, like a sort of psychedelic tease. Because of this, I've wanted to try BDFLY in combination with a threshold dose of mushrooms, to induce a more provocative, meaningful experience, which I have yet to encounter with BDFLY alone.
However, it also has a lot to recommend it. The pros don't need as much description as the cons, so I think I can just list them briefly:
-Mood lift
-increased self-confidence
-Very nice CEV's and OEV's (though the visuals from BDFLY seem to look more "synthetic" then those of other psychedelics)
-Increased mental spontaneity (more amphetamine-like than psychedelic)
-Conversation enhancement, what you and others say seems more insightful
-Mild time-distortion
-(I'm sure there are others I'm forgetting, but this post is too damn long already, sorry guys

)
One important warning about mixing BDFLY w/ other substances, with two examples. I think that BDFLY definitely has a more delusional quality then most psychedelics, so be careful what you mix it with. In one case, a friend of mine, to whom I gave a dose of 350 mcg, decided to eat a fairly potent edible two hours after dosing, became delusional, and apparently had a painful psychological breakdown after he left to go to his boyfriends house (had I know this would happen, I would have tried to prevent it). Also, I once made the mistake of getting stupidly drunk at a party with some friends on the tail-end of one of the trips, rationalizing that it would help me fall asleep. Instead, the stimulation caused me to drink way too much because I didn't register the alcohol, and I apparently went completely nuts, convinced that I was over 300 years old and cursed by God; completely manic, yelling and delusional (though not violent). Stupid of me, but now I know better, and hope others won;t make the same mistake.
Anyway, my feeling is that BDFLY is best as a socially-oriented/lighthearted psychedelic, or perhaps as a platform for deeper, more meaningful experiences when combined with other psychedelics (conservative amounts though). By itself though, I don't think you can reach those levels without taking a dose that will take a definite toll on your body, 600 mcg already feels borderline-toxic during the come-up for me (though I probably will try higher doses at some point).
~and if anyone has read this entire post, I am deeply grateful for your patience, I tried to pare it down as much as possible~