I'd say that it doesn't look comfortable at all but on the good side it looks aero-dynamical and that is probably the reason for the added speed. Personally, I am not that much into speed. I like to go fast but my bike is heavy and tires are wide and I think that rolling resistance or whatever you call it is not on our side (me and my bike) so I do not need this piece of equipment. Especially if you consider the fact that I have some back pain from time to time.
If you properly set your bike up with aero bar they are very comfortable. I used they in all my ultra marathon races 12 / 24 hours. As far as back issues I have had bad back issues since the mid 90's after being hit by a car. I live with back pain everyday but when I'm on my Tt bike it helps flatten and stretch my back out and I can ride forever with no pain. The bar aren't for everyone but I love them.