Looks like online everyone recommends GoodSync but is it really that good ? Anything else that is better ?
Oh yeah want to backup my WD 4TB Black hard drive to my WD MyBook 4TB external drive.
They all work about the same way and have quite similar functionality and configuration options. You set up what amounts to a profile of you want to do and then run the profile periodically.
If you are copying a group of files from drive A to drive B, you have to decide if you would want File X to be deleted from drive B if it is deleted from drive A. I would, but some folks like to keep a copy of all deleted files on the target drive. That configuration choice should be available in any decent product.
But they will differ in areas such as interface design, quality of the help file, and ease of use for a newcomer. Most are free.
I'd suggest you download 4 or 5 of the usual suspects and give them a test flight. Most likely there will be 2 or 3 that put you off immediately. Eliminate those and drill down into the remainder.
I use FreeFileSync now, but used Second Copy for 10 years without incident. Second Copy has a great uncluttered and highly mature interface, but I eventually went away from it due to OS support and price ($30). FreeFileSync (from Sourceforge) works quite well, but the interface is a bit busy. I've got it set up to run with one click using the batch file capability built into the program.
Here's a few more you might want to run down and look at. I haven't looked at all of them:
Allway Sync
Folder Clone
FBackup
Syncback
Synchromagic
Facebook
Twitter