(sneaking quietly out of lurk-dom)
I am still relatively new to sock knitting but I use only circulars - usually two but sometimes three or four for toes and heels depending on the pattern. I knit quite plain socks but I found the DPNs very hard to manipulate, maybe because with a 9"+ handspan my hands are just too big?
As I often knit when I travel by train or car I find the circulars great. No lost needles, no possibility of dropping stitches or pulling needles out when unpacking (all of which happened more than once on DPNs). But as I read all these answers I wonder what I am missing. Most posters here seem to prefer DPNs.
I am currently using Addi Turbo circulars and it took a while to get used to the very short needle length, but now I just roll up my current sock project and take them anywhere in my pocket. I can pull them out and work anywhere. I assume that others feel that way about DPNs too. So . . .
While I am not planning on changing how I knit particularly, I am curious about WHY so many prefer DPNs. Is it because that is what they learned on or are there other advantages I have missed? Just curious.