I've always been a huge Clarks fan..  even the cheap china ones still look great, fit well and last quite a while.
These are teh first Un.- models that I've tried from them.  The traction is better than any shoe i've ever owned.  I live in snowey, wet, cold northern Wiscinsin, and these offer better grip than any of my snow boots do.  I'm not sure what the sole is made from, but its awesome.
as far as the rest of the shoe goes..  its very light, and quite stylish.  i like the slightly narrowed but moderately squared off front toe.  it looks like a dressy but easy on/off 'biz-casual' shoe should look like.  i wear these most days, and with work slacks and a button down it fits in perfectly.  and with jeans, it also looks good without bing too much.
if these hold up like most clarks do, i will be a happy camper.
-is it worth the extra $20 more than the regular line of Clarks..  I think so.