I use WD Red 3TB drives in my RAID5 array - never had any issues whatsoever. Highly recommended.
If you own only one raid array then you don't have a large enough sample to have good statistics. You need to look at hndereds of arrays.
You just have to decide what kind of failure you can live with. Canyou wait while an array rebuilds? Can you risk having no redundancy after one failure? Many people will decide they need two parity drives (raid 6) to they still have redundant drive after a failure. Others will decide they need two arrays and keep them sync'd. Other will want three arrays that are geographically dispersed and kept sync'd.
And you STILL need to find a way to back this all up.