Well I wouldn't by the Iwata from that site. That costs a fortune. If you are going to get an Iwata hakama, get it from the manufacturer at the site below.
In all honesty though, I don't think there is much of a difference. If the Tozando one is cheaper then I would get that. Having said that, I own 2 Iwata hakamas and I am very happy with them. I got them because the Iwata shop was closer to where I was living (Iwata is based in Tokyo, and Tozando is in Kyoto, I think.)