We have been talking about this a couple of times lately so I just wanted to tell you I finally cast on, show what it looks like so far and give my first impressions. CON: Definitely less portable/more tangly than doing it on DPN's. PRO: Both socks will be done at once!
The concept is pretty much the same as knitting on 2 circs but a little more shuffling involved. Also, the needle I have is 42" I think...I know it wasn't in the 50's which I looked for but I would definitely recommend the longer needle. The 42" is the minimum I would use, due to the way it sits while you are working on it.