I love my DPNs and find that I can knit faster using them, but that is just because I am used to them. When knitting larger project I use Circulars. Have completely stopped using straight needles, use circulars for everything.
At the moment I am making a sock for my 2 year old using DK wool using a 32inch circular (the only needle I had in the size I needed) so forced to use the magic loop method. and it works well so with a bit more practice I will probably get faster.