I have something similar to that at my house, but its made out of plasitc with armrests molded in with the rest of the chair. There's a padded piece that velcro's onto the back and seat position, but I still find that it's too hard to sit in for long periods of time. The pic you posted looks like it would be very comfortable to sit in, but personally I prefer to have armrests in whatever chair I'm sitting in. I'm not suggesting you go out and buy my crappy plastic ones, just that you might want to look around for a model that has armrests if you usually use them.
