I believe you mean 'better option'.... rather than more reliable
I don't think there'd be much difference, only 2 x hlg 320s are slightly cheaper than 1 x hlg 600 and you'd only need 1 plug on a.c. side - that's if you're sourcing the drivers separately.
Also 2 x hlg 320 drivers means you can have 2 separate lights for 2 different grow areas.
Maybe others could chip in with their thoughts on 2 drivers v 1 driver setup.
Hlg 320 is my biggest driver, I prefer smaller lights that I can drop in when needed but that's just me