I have an iphone 5 with both an Lightning to 30-pin Adapter and a Lightning to 30-pin Adapter (0.2 m). They do NOT work the same way. I have a DICE in-car system that has a 30 pin connector cable for connecting an ipod or iphone. It has worked fine on all ipods and all iphones through the 4S. So, obviously had to wait for the lightning adapters came out when I got a 5. Ordered both the the 30-pin/Lightning adapter and the 30-pin/Lightning cable. Have both in hand now and tested each with my in-car 30-pin cable. The 30-pin/Lightning adapter works flawless. Audio and charging work perfectly with the iphone 5. Thankfully.
A different story with the 30-pin/Lightning cable. When using this cable, the iphone reports "accessory is not supported". Charging does work, but no audio out. Tried it in every conceivable configuration of car stereo/ipod/cable insertion orders you might imagine. Nada.
So, the 30-pin/Lightning adapter works perfectly and the cable version does not support audio and reports "accessory is not supported".
Something is different between these 2 adapters. I tried swapping between both adapters about 30-40 times trying to figure it out. Assumed it was user error for the first 10-15 times, but now I'm convinced there is something different between the small 30-pin/Lightning adapter and the 0.2m cable version of the "same".
I hope as more people get there's and test it, we'll figure this out. If anyone has any ideas, I'd love to hear them. If you are still deciding or waiting, just be aware, that at least one person (me) is having these 2 adapters behave differently with the same exact accessory.