Replace optical drive with hard drive in mid 2012 non-retina MacBook Pro Is it OK to replace the optical drive with a hard drive or SSD on Macbook Pro 13-inch mid 2012 (non-retina)? I heard it's buggy.

I have already replaced the hard drive with an SSD and it's now much faster.  I'm thinking of replacing the optical drive with a Hard drive or SSD and use it for secondary storage with a Kit you can get out there.  However, I heard it's not a very reliable fix and disconnects all the time or something like that?  Anyone could please give me any hints on this?
I have heard of certain WD drives having hardware aggressive power saving features where the drive will shut down after a rather short period of inactivity. Worse, it doesn't tell the OS that it's doing so, so you get into a 'wait race' where the drive is waiting to be told to spin up, and the controller is waiting for the drive to signal 'ready'.

This usually isn't a problem if the computer shuts down the drive to save power:  It then knows that the drive isn't ready, and sends the appropriate startup.

Try asking with more detail:  Drive, kit, etc.