I've practiced with dpns but haven't done much with them so I guess I'd have to say I prefer circs. While I think both are useful to be competent with I haven't worked much with dpns because it hasn't been necessary. I tend to not learn something new until I actually need it. Then it's crash course, do or die time. I started knitting in the round with circular needles because I had them. My interchangeable set lets me use whatever size I want in various cable lengths. For some small diameter knitting I can see that dpns would perhaps be preferable. Another thing about dpns is that you can drop and lose them (my chair loves to eat knitting needles, crochet hooks, stitch markers, scissors, remotes, etc.) but with circular needles both tips are connected. I think of them as easily retrievable needles on a leash.