I know some have complained about the grip feature of these cleats, but I have had no problem with mine. On long rides when I find myself walking on a slick store floor while taking a break, these are an improvement over the traditional Keo cleat. They work.
I like the Look pedals because they're easy to use and it's easy and inexpensive to replace the cleats. You just have to remember to lubricate the screws before you screw them into the soles of your bike shoes. And once a month or so it's a good idea to loosen the cleats and re-lube them. It makes it that much easier to replace them when they're worn down.
These cleats have served me well since I began road cycling in earnest several years ago. The addition of the grip rubber is just enough to keep you from shattering a femur or faceplanting on tile or hardwood floors. The gray version has a certain degree of float (less than the red, more than the black) which will help to save your knees from undue stress while turning the cranks over time. I've never had any issues clipping inout. I use them on a variety of shoes and in a variety of applications from commuting to time trials and triathlons. Take a pen and mark the outline of the cleat whenever you replace them because it does take a little time to get cleat position just right. This trick will save you that time and effort.
Using the cleats on the Keo pedals with the carbon blade for a spring. They work as expected - clip in well, stay clipped in, clip out with a proper amount of force. Rubber on cleats helps with walking. Rubber wears out in about a year for me (about 5k miles), and by that time, some of the cleat is gone, too, but not so much that the cleats don't function.
My current cleats are the Look 4.5 degree float(gray color) which is great when I was less experience of a rider. Now a days, it feel like I have too much movement as I am focusing on a more efficient pedal stroke. Thought I switch to the zero degree float since my 4.5 degree float cleats is about to wear out. I'll have to update this review after I install them.
As long as you're riding, not walking, this is the cleat for you. I've never had any knee problems and the transfer of power from foot to pedal is something you can definitely feel. Better than the original Look system.
The 9 degrees of float is very comfortable, and I would definitely recommend. This order was sent out same day and I received it in one day with free shipping! The customer service is excellent, I definitely recommend this place!