I'm using Magic Loop to knit my sock pal's socks -- one at a time, because it's my first time using this technique. My impressions so far:
It's easy. If you really know how a sock works, you don't have any trouble figuring out which needle to use when or which needle to pull out.
It's handy because you only have one long needle, not 5 out of which 1 invariably gets lost.
It's supposedly better for the join because you don't have gaps between needles. So far, I'm still getting gaps between needles, and worse than with DPNs. But maybe that'll get better with experience.
Once I figured out how to make the cable hang down instead of sticking up and getting in the way, things got a lot easier.
This is still a bit slow for me, but the longer I do it, the faster I'll get. Practice, practice, practice!
Next up: pictures of socks. I really need to hurry up to get them done in time for the deadline!