Hello everyone, i see this is an old thread but there seems to be alot of guessing and misunderstanding here...
I have (2) 500gb samsung 850 evo's in raid 0 for almost 2 years now, and had no problems with them except once when we had a power surge, i had to rebuild the array and it was actually quite easy, i lost no data.
One of those drives is actually 9 months older than the other, but honestly the 850 evos are such a reliable drive i see no issue with this array working for a decade.
So ive gained a reasonable boost in speed, 1tb of storage on a single system listed drive instead of 500gb (if was raid 1)
Keeping all of your important data backed up on another drive or in the cloud is a must if you choose to do this, I keep all of my critical data away from the array on separate backup drives, so no problems there. If i lose the array i will NOT lose any data that matters cause its all stored separately.
This setup may not be for everyone, especially with the nice sales on high capacity ssd's these days, but it does work and boy do i love that my games load in a blink... And i dont have to wait for the slow boot-up / compatibility issues of an nvmE drive