I used some unsupported SATA drives in a RAID enclosure and while they work, we have issues booting the server sometimes. When the server boots, the RAID initializes and sometimes not all of the drives turn on. It usually requires a cold boot and then a warm reboot (or two) to get it going. Which drive(s) don't turn on is pretty random. Has been as many as 3 that don't turn on initially.
With the supported drives (that were smaller) everything worked fine. We contacted the server/raid manufacturer and the issue may be addressed in a future firmware update to the RAID, but we aren't sure.
For the application we used these drives for this was acceptable, but there are definitely applications and data that we would not be comfortable with a similar situation.
So really it depends on how important the service and data is that are relying on those drives. What kind of compatibility and support requirements do you have?