I recently bought a Seagate Goflex 3TB drive for $119 at Costco. Paid no tax because I got it on our states Tax free day. I bought this drive be cause I can later buy an adaptor that will make it a Thunderbird drive ( I have an iMac). My advice is get the most storage you can for what you’re paying. Both WD and Seagate make decent drives.
The WD My Book is better for use as a Network File Server device, IMO, primarily because of the software.