The company I work for uses wireless, hand-held computers with a built-in scanner for order picking. They work fairly well but we took to calling them "phasers" for their resemblence to the Star Trek weapon (only twice as large). The 2 biggest drawbacks for these units are the size and the lackluster barcode capture (it uses a camera to capture so you have to hold still). Retail price for each unit is ~$3000 USD (not cheap).
We looked at an off the shelf wearable computer which mounts to the wrist. These type of units are much smaller and the barcode capture is virtually instantaneous. Since everything mounted to the top of the operators arm or hand, they were able to use both hands to physically pull product from the shelf. No more holstering the phaser! This unit has a major drawback though. In the everything smaller is better world, some engineer thought a 2.5" screen size would be the perfect match. Unfortunately, at that size about the only thing it will do is make you go blind from trying to read the screen prompts. While the price is comparable to the other unit at $3500, the small screen means re-writing program codes to fit the miniscule resolution (IT work ain't cheap).
We decided to keep the ring scanner (Bluetooth version) and pair it with a desktop PC and monitor. We mounted them to the pick shelf so the operator can move the screen as they move across the pick face. The scanner is worn on one hand (only 2 fingers and a thumb required) and a wireless mini keyboard is on the wrist. Viola, a hands free system just like the big boys make but for half the price (~$1800). Yeah I can't go anywhere in the warehouse with it, but we are just interested in picking high volume items from a 20 foot long pick face so it works perfectly.