I have to say, in my very limited experience (as in, I've only got the one speaker) - the Jawbone Jambox is awesome!
I just got it yesterday, so I'm still playing with it, but my initial impression is: Kewl!
It came with two USB cords (a short and long), a PC microphone cord and a power adapter (to use with the USB cords). You can charge it either via the USB->PC or via the power adapter. It's designed to link to your iPad via Bluetooth.
It paired right up with the iPad and the sound is great. Now, I'm not an audiophile, by any means, so I can't give you any specs. But - it sounds clear (even with the volume up high), the volume does go pretty high and the bluetooth range is great.
So, again, based on my one day's experience: the Jawbone Jambox is superb.
Marilyn