It is not peer to peer, unfortunately, and I am not aware that such a USB connection yet exists. It is a very fast and reliable access system and the transfer rate is close to direct HD access, exactly what I wanted. Going on a trip for a few days I just transfer (via a batch file) complete directories and thus I have all mail and important docs I use on the home pc with me. On return it is just v.v. and it takes only a few minutes.
No, the electricity bill is not that much as I have most peripherals off when not in use, the great advantage of USB, the hot connection. Actually, this is one of the reasons I am transfering everything (or at least everything possible) to USB.
I run Epson Stylus Color (which does not work with USB), an old fashioned impact printer for draft prints on endless paper and a color laser printer (which does not work on USB either).
The SCSI connection to my scanner (HP Photosmart, IBM A3 Flatbed) works perfectly ok.
BTW, the USB Hub needs to run on own AC adapter only for a few devices, not a single one I have attached.