Wow, you ask a question!
First off, shooter fair comment about power cords etc. I've been really impressed with the AE sound quality through my CA kit. I originally ran my desktop to it from my back room (maybe 5 metres or so) and it worked well, though dropouts did occur and lasted a few mins (impossible to listen to). Through optical it sounded crisp, clear and punchy though perhaps a little too much energy(could be the CA kit tho) into the back of my 740C.
I also had problems feeding spotify through airfoil so decided to go for the laptop option. Hardwire it into the amp, no more dropouts. I've got no optical out on the laptop and the usb connection through the Dacmagic is a little disappointing so I thought laptop ethernet>AE optical>DAC>amp. It works a treat, sounds good and streams solidly. Job done. Just thought the ethernet cable I'm using free from TalkTalk might be improved upon as cable changes I've made elasewhere in the chain have definately made a difference. Despite a shaky start, there's been some helpful suggestions and I'm grateful for the advice. Think I'll stick with the cheap cable, sounds good. But not quite as good as the wi fi connection from my desktop, which is why I asked.
Just my opinion of course