I had one on my hornet before I sold it and you wouldn't even know it was there when I didn't have something plugged into it. You don't have to have it hanging off your handlebar. I used the charger for a 12 volt port. If you just do the usb, you won't have as many options down the road (for what I don't know), but also, like the previous poster pointed out. I'd really only do one device, and going with that 12 volt cig adapter gives you a really wide variety of devices that go beyond the USB port, in the case of an emergency, say like a tire pump, offroad light, or even some other "emergency" type device.
If you look in this first picture here you can see the adapter, with it's waterproof lid (held tight by the white zip tie).
If you look in the other picture with my old GPS tell me if you can even tell where it is wired? Nice clean installs are just a matter of prep and planning.
88 Blue Hawk (NT650) Project Pics - http://tinyurl.com/clw8h3q
2000 DL650 - Being ridden but make me an offer if interested...
2002 DL1000 V-Strom