These are the best shoes I have owned in a long time. I got them on sale at REI (they don't carry them anymore, though) and have been wearing them almost every day now. The lambskin lining is like butter and the outer leather is high quality too. I mostly wanted to get a pair of casual shoes for work that would stand up to a fair amount of walking on my commute. The ventilation system feature seemed kind of gimmicky at first, but it really works. That said, I did experience some water intusion as I walked through a puddle on a rainy day. It didn't seem like that big of a deal to me, but if you live in a wet climate it might be an issue you want to consider. Overall, I would totally recommend these shoes to anyone looking for a comfortable, stylish pair of casual shoes.
Here's my Pro and Con list:

Pros>
~Extremely comfortable out of the box; wear them all day from day one
~High-quality materials & workmanship
~Feet stay cooler
~Modern styling

Cons>
~Water does intrude into the air vents when walking through puddles, so these are fair-weather shoes only

SIX-MONTH UPDATE:
So far, no changes to the previous review; stitching is holding up nicely and soles are not wearing too fast. Most of all, they are still comfortable.

ONE-YEAR PLUS UPDATE:
Shoes are still wearing well, considering I wear them almost every day. I just purchased another pair of these to replace the originals when they finally do give up the ghost, since Clarks will probably at some point discontinue them. I looked at some other Clarks unStructured shoes that are similar design at a department store, but they didn't seem as well constructed as these.