Pros: Sheds mud great and light weight. For a full carbon $199 is a good price point.
Nice cleat float up to 20 degrees

Cons: Stack height and pedal compound doesn't take well to direct hits. NOT compatible with all MTB spd based shoes. Check compatibility here:
http://www.lookcycle.com/quartz/en/popsetup.php
As your shoes wear the pedal engagement will change too.
Not great tactile feedback for being engaged, easily disengaged at the wrong time...and no tension adjustment.

Recommendation: Been riding Looks since 1986..and have never deviated for road use..now on Keo Carbs...BUT...
I got these Quartz Carbs when I bought some new SIDI Spiders....ooops didn't fit unless I wanted to cut out and modify the tread on $350 shoes...nah, no thanks. LBS was baffled with the set up..so I tossed my old Shimano 225s at them and they set it with the correct shims. Didn't get the tactile feedback I got from my Ritchey WCS V4s. There was a stack height situation that I ran into..as small as that may be, I made far more pedal contact than I had with any other design. BUT it shed mud well.
Forces you into a dedicated selection for pedals if you have more than one bike as opposed to cross pollinated SPD designs/cleats.
I yanked them as I lost confidence a few times when the pedals released at the absolutely wrong time. Took them back to the shop for a refund, and reverted back to WCS V4s with comfy SID shoes.
Shop owner went through the same process himself and also abandoned trying to like them.
I wanted these to work..but also wanted the shoes to take priority.

Pros: Light weight, mud sheading, Once set up the pedals engage and disengage flawlessly

Cons: Takes some time setting up the correct cleat height

Recommendation: a great pedal which is smooth, light and works flawlessly, just get someone who is knows how to set up pedals for you on this one. These pedals do require you to set them up right.