eflaten wrote:
As I understand APFS should be used on SSD as it is better.
Personally I would avoid using APFS on an external drive unless you are going to install macOS 10.14+ on that drive. APFS is a new file system which is still experiencing growing pains. Many times the APFS file system becomes corrupt where Disk Utility First Aid is unable to repair it. Since Apple has not released the necessary AFPS documentation yet third party utilities are not available to repair APFS so this means you would need to transfer everything to another location and erase the drive in order to "fix" corrupt APFS file systems.
APFS should be much more reliable due to how it works plus it should work better with SSDs, but at this time I don't trust it for the reasons mentioned as I've seen APFS file system corruption occur way too much on our organization's Macs and Disk Utility could not repair it. This resulted in performance issues with the drive and with one drive it would cause kernel panics when connecting it to a Mac which made it extremely difficult to access the data.
If you need to use the proprietary Samsung software for the reasons @steve626 mentions, then make sure to keep this software up to date as a macOS update or upgrade may temporarily break the proprietary Samsung software causing you to temporarily lose access to the data until the software has been updated.
Make sure you have a backup of your external drive if you are storing any important and unique information on it.