the hummingbird is quite a crafty yet simple idea. Floss on a stick!
The whole point is that it's now much simpler to floss, none of that fiddling about with huge lengths of floss. Also if you have large hands or poor manual dexterity it means you have more chance of being able to utilise floss.
The vibrating aspects of the flosser also helps to ease it between the teeth.
But now for the negatives...
the floss is actually rather thick, which means if you have tight contacts between your teeth you might not be able to get it between you teeth anyway!
secondly it isn't particulary cheap £4.99 for the starter pack then £2.50 for 10-15 refills. Working out approximatley £5-10 pounds a month.
But then it's worth that amount of money to keep your gums healthy and breath fresh!