I don't know what kind of biometric auth systems you used, but I used to work for a company that did professional AFIS systems and on the side some fingerprint auth solutions including usb readers, and they were damn fast and convenient.
I imagine it must depend on what you use. There's consumer grade shit like apple's or MS's fingerprint scanners and software, and then there's pro stuff.
Plus, to the guy that said ADN was secure. It's not. Fingerprints are far more secure (the gummy bear trick and others have been taken care of quite some time ago), since they're actually unike, unlike adn (twin brothers come up as matches, for example).
Another option would be Iris scanners. Retinal scan is more invasive and you have to put your eye up to a reader.. Iris scan can be done with a simple camera while you look normally at your terminal screen, and it's pretty fast.