There are still 2 major brands - Seagate and WD.
You would be better off looking for CMR drives (which are faster than SMR drives), instead of 7200 rpm.
The WD Purple 4TB is CMR 5400 rpm. You can double check the model code on WD's site since they are more transparent about CMR/SMR these days.
The Seagate Barracuda will definitely be SMR. The Skyhawk might be CMR depending on model code.
