I don't have much experience with Onitsuka Tigers, except for a pair of Ultimate 81's that I love.  The U81 may be slightly long for me, but it's somewhat narrow and fits my narrow foot well.  In contrast, the California seems bigger in every way.  It seems longer, wider and heavier then the U81.  I'm going to exchange them for a half-size smaller and hope they're still not too big.  I'll update this review after receiving the smaller size.  Update:  One-half size down is perfect, so I wear a 10.5D in the California and an 11D in the U81.  Any thoughts of sizing down with the U81 are now gone, because they would certainly be too small.  Other then size and appearance, the biggest differences with the California are that it has more cushioning all around and probably a big more lift.  It's more typical of later running models in these ways, and since it was introduced at a later date (I think), I don't find that surprising.  So far, it's really comfortable and I think I'll like them a lot.  Although it's heavier then the U81, it's still quite light compared to most running shoes.  I'll also note that these have a lot of arch support, which I like.  They probably have more arch support then any shoe I've owned in a while.