From the thousands of threads I've read on the differences between each of the HPFPs, the one thing that stands out for the APR & LOBA pumps is
quality.
The HPFP works at by compressing fuel at high pressure (in the name), both the APR and LOBA pumps have a better sealing system which helps to prevent fuel and oil mixing.
There have been more cases of Autotech HPFPs failing and allowing fuel into the oil, then there have of APR & LOBA (although LOBA hasn't been on the market that long in fairness)
If fuel mixes with the oil it will (and has proven to) cause serious engine damage
If (read as when) I come to buy a HPFP it will be either APR or LOBA for that reason