Dell Brand Internal Sata Hard Drives, are they any good (from personal use not assumption)??

Dell does not make any hard drives.  They purchase them from companies that do nothing but make hard drives.  Western Digital is one of their sources of drives.  I am looking at the specs for 1o different Dell computers I have randomly setting on my desk.  Of those, 4 have Seagate drives, 4 have WD drives and 2 have Toshiba drives.

While Dell may sell you the drive, they did not make it.  WD or Seagate did. 

Dell doesn't make hard drives - they buy them from the lowest bidder, and then put their logo on them.

If you buy a Dell computer or drive, it might be a Seagate, WD, Maxtor, Samsung, or Hitachi.

I haven't had a SDD fail (yet) but I run 2 backups at least (cloud and direct disk copy).  SDDs   will last as long as a HDD or to your next upgrade.

I work with Dell, all the drives have Dell part numbers but all are from some other manufacturer, they don't hide it, the alternate part number and manu is usually there, usually Seagate.

WD is better..............................

Uhhhh....Dell does not make hard drives.  Dell sells hard drives that are labeled "DELL".  At least some of these are made by Seagate, but it wouldn't surprise me to learn that WD or Toshiba or Samsung or ?????? also make hard drives labeled "DELL".

I don't think there's a dramatic difference in quality from one brand to another.  All mechanical hard drives fail eventually.  Sadly, it seems (so far at least) that SSDs are not any more reliable.  They are sometimes faster, but (from my professional experience) they fail as often as mechanical drives.  

If I found a good deal on a hard drive or SSD, I wouldn't hesitate to buy it if it was labeled "DELL".  But just keep in mind that any mass storage device will fail, so buy as cheap as you can and buy 2 or 3 at a time.  Use one to make periodic backups of data from the other one...