It is far more likely that the moving parts of a mechanical hard drive will fail before the solid state parts of a hybrid drive. I worry about any mechanical HD failing, and haven't had a system relying on a lone HD for over ten years. Instead I RAID 1 or RAID 10 2-4 HDs for insurance against failure. I will use a separate single SSD or RAID 0 array for data I can afford to lose (like boot drive) where performance is more important than reliability. These days there is no excuse (cost, performance, reliability) to rely on a single mechanical HD for anything, just don't do it. There are faster or more reliable or both alternatives.As someone who is using WD Gold drives in my Desktop / gaming machine, I'm hesitantant to have one with SSD memory. What happens to the drive if the flash memory fails?