I love the design and feel of these shoes.  They look great and feel amazing.
The lifespan is about average compared to other sneakers I've owned.  As is typical the soles wear away eventually and in the mesh style (of any brand sneaker) my big toe usually works a hole in the material.  Onitsuka is no better or worse in that regard.
What I LOVE about the feel of the shoes is the weight.  So light they're almost weightless you feel it as soon as you put them on.  The other thing you'll feel immediately is the ground.  This is an important point because some people might not like that fact but I love it.  I feel connected to the ground almost as if I'm barefoot (but with more protection from sharp things).  I live in NYC and walk on a lot of pavement so you would think the thin sole would bother me but actually I find my feet feeling great after a long day of walking around.  Maybe this is that whole principle of a thinner shoes making your foot muscles stronger - I don't know - I just know that I like the way it feels.
Oh and the look of these shoes is sick (ie. incredible).  I put in the yellow laces (that come with the shoe) and they look great!