I've ridden on a Nashbar carbon fork and an Easton aftermarket fork. Both held up fine. I'm now running a Salsa steel fork on my touring bike and a Salsa in-house full carbon fork on my 'cross bike. I trusted the Nashbar fork the least and used it for a year before I could replace the entire bike.

The gold standard for forks is name. Any of the major fork manufacturers are going to have a better quality check than the online cheap stuff. In general, these forks are carried by reputable LBS's because the LBS is also lending it's name to the quality of the products they sell and certainly have more to lose than a knock-off Chinese company.