First, I'll say that so far, it's saved me a couple of screamed awake wake ups because my LOs limbs were caught in the bars. She's moving around a lot now and there have been a couple of nights recently where I have seen her legs fly at the bars. Bumpers are certainly a good idea.
The material is decent quality, no funny smells, no weird marks.
What bugs me about it is that it seems that it's not all even. When I attach the sides, it's warped somehow and so there's a saggy bubble on the outside... it's hard to describe. The inside of the crib is perfect and I'm sure if I fiddled around with the bumper, I could get it the way I want... but who has the time?!
I would also say that it's a royal pain in the posterior to change the sheets with this bumper up. When I lift the mattress to swap out sheets, it's pulls the bumper up, and when I set the mattress back down, it pulls the bumper down. Lots of fussing to get it back in place again.
I think they could improve the product buy adding something that allows you to attach the bumper to the top of the sides of the crib rather than to just the bars.