Strengths: Super stiff and fairly light when equipped with the proprietary monoblock cranks. Finish is second to none. Ahead of its time when it comes to bottom bracket size and stiffness, as well as its rear triangle design, spacing the frame from the wheel. Look proved this theory in wind tunnels.
Weaknesses: Tightening the proprietary headset is finicky, with two bolts tightening down on each other. Mine came loose once. You can feel the play. In addition, you will need to properly tighten the stem to full torque setting. A loose stem bolt could result in your entire aerobar assembly falling forward and down . . . . Ouch! Other weakness: Super expensive if bought new. My model year requires use with proprietary ZED pedals, so I couldn't use my much loved Shimano DA pedals, which clip in a little faster IMHO.
The only reason this super bike is not more popular is that not many pros used it or won races with it. This is because Look doesn't invest much money into paying pros to ride their bikes. That doesn't mean their products aren't revolutionary. This bike is not made in Taiwan. It's special and different. I chose this bike over a Cervelo P3 and P4, and have no regrets. Weighs 17.98 lbs with pedals and Zipp 404s. I also have a Look 585 and I'll never sell it.