I think it's a personal preference, also a matter of what you're making. I prefer shorter ones so they aren't as unwieldy, but I only use dpns when whatever I'm making gets too small for a circ.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry