The material the sleeve is made of is interesting, and you can tell some thought has been put in to choosing it. My macbook air fits snuggly into the sleeve; there is not too much movement once the notebook is in the sleeve. I have faith that this product will play a part in protecting my preciousssssssssss from any bumps, due to the shock absorbing material.
Additional things to consider:
The product is compatible with the MBP Retina 13in. The sleeve does very little in the way of waterproofing. Wasabi Green isn't everyone's cup of tea (but I think it's awesome, and the design though minimalistic, is nice).
Overall, I would recommend this sleeve as an affordable protective layer for your MBA when you're out and about.