I had this chain guide on a 2008 Turner DHR, it was a lightweight option to the E.13, and looked sturdy out of the box. It ran flawlessly for a few months, then I had to adjust it a few times, because it would drop a chain especially when things got muddy. When back-pedaling in some trail sections that were muddy the chain could get stuck and cause a real issue. Luckily I've never used this guide in a race, but I have seen it fail under race conditions on friends bikes....
Also, on my particualr guide, other than dropping the chain a sometimes it was fine. The guide is a strong plastic, and the black color comes from the backing, which will began to chip away around the edges, at least mine did after a year of use. There was also one hit the bashgaurd took when riding Boondocks at Northstar, the gaurd around one of the chain ring bolts had splinted inside, and caused a cracked looking part around the chain ring, however the guide held together fine. I think the plastic can absorb hits easier.
The guide is a great price for the product. And would recommend it if your always in dry conditions.