Every single time I format a new HDD (few times a year), this popup gets me:

It defaults to MBR (why?), yet research would indicate that GPT is the smarter option.

I did the research so you don’t have to.

Without any of the technical backstory (seriously, we don’t actually care), here’s your decision process:

If you’re formatting removable media, i.e. a USB stick, pick MBR

You cannot use the GPT partition style on removable media.

If you’re formatting a boot drive for a modern OS (Win7, Win10, etc), pick GPT

You should use GPT unless you’re building a machine to run old OS’s on purpose.

If you’re formatting a drive larger than 2TB, pick GPT

GPT is also required for disks larger than two terabytes (TB).