It seems to me that the propellers are the most important thing on the drone and minor imperfections could cause catestrophic failure. Shape, balance, flex, fit all come into play with these components that keep your bird up in the air and controlled. While it is possible to make propellers better than DJI's OEM props, of the reviews I've read the 3rd party propellers almost universally say they aren't as good as the DJI props.
Having said that, right now there seems to be a drought of DJI props and the prices are either jacked significantly or priced at $12 with ridiculous shipping charges. A few weeks ago on Amazon DJI props were $12. Yesterday $17. Today almost $20. Best Buy has them for $13 but if shipped $5.50. $15 on Ebay with free shipping currently.
I am intrigued with the carbon fiber propellers that some vendors are offering. Plastic is easily deformed and retains the deformity if held in an unnatural position for any length of time. I just experienced having one of the blades become quite misshapen even though I am very careful when packing and storing my mini. I was lucky to have caught it before a major catastrophe. I'm wondering if the carbon fiber props are manufactured to high enough standards and will withstand the propensity for deformities that plastic does?