I ordered two pairs of Onitsuka Tiger sneakers last spring from Nordstrom. I kept the Onitsuka Serranos (reviewed here) and returned the Ultimate 81 sneakers that I am going to review now. Onitsuka Tinger Ultimate 81 sneaker is roomier and probably more fit for people with wider feet. It is definitely more comfortable for the same reason. I ordered the same size from both lines, but the Ultimate 81's were around half a size bigger on me. I would order half a size smaller.
The ultimate 81 looks clunkier and wider in general, which gives it sportier look that might not be for people who are looking for slimmer design. I really loved the details of the Ultimate 81. The inner lining was plaid and could be seen around the top if you look at closer. And the neon green bottom adds more character to them. I could not keep them both, so I decided to keep the slimmer one, but if I were looking for something more comfortable, for example for the hospital, then I would definitely pick the Ultimate 81 design.