It depends which HZ calipers you're comparing.

Most HZ got the PBR alloy caliper, which was rubbish. Later ones got the Girlock alloy 'Collette' caliper which looks similar to early Commodore calipers; these are much better.

The only difference between the HZ Girlocks & WB Girlocks is the attachment of the hose. HZ use 3/8" UNC thread, while the WB uses a 10mm banjo bolt differently located to the 'side' of caliper housing. Otherwise they share the same pads & mounting & are as good as each other.

Dr Terry