Need recommendations on External Backup

Hey everyone! I currently have a Drobo connected via ethernet. I am looking to switch to WD and overwhelmed with the options. I think I have narrowed it down to these 3: My Cloud Expert Series EX4100, My Cloud Pro Series PR4100 or MyBook Duo.

These are the things I need:
Raid 5 preferred/mirroring
Ethernet connection (not usb)
Not a fan of the cloud. On the My Cloud products, is everything stored and pulled from the cloud when working?
I don’t need to share files with anyone…it’s just me
I’m on a mac

Can anyone give me pros/cons of the 3 products I listed with the requirements I have?
Thank you for any advice!
~Cyndi

Hello,

The WD My Cloud products serves as your personal cloud storage. WD My Book Duo is an external storage that does not possess NAS features: https://support-en.wd.com/app/answers/detail/a_id/19649