I like bern hard hats because they feel the most comfortable. Also, there is some engineering behind my preference:
Most helmets protect you in two ways:
One; they distribute the impact over a larger area of you head. To improve this, the stiffer the shell the better (e.g. composite shell beats plastic shell). Shame composite shells cost so much.
Two: They can fracture and the process of fracturing absorbs energy. BUT, if the helmet/liner doesn't fracture then this method of energy absorption won't happen. The foam liner will absorb some energy by compressing a bit, but not to extent that it would if it fractures. The 'squashing' of the liner will also damp the acceleration of you head which will help protect your brain. The Bern hardhat liners don't fracture but can 'squash' a lot. This should mean that in a crash which isn't hard enough to fracture the liner a 'hardhat' type liner should protect you more than a regular one. But if the crash is hard enough to fracture the helmet/liner then a regular foam liner will protect you more than a 'hardhat' type liner.
Its a personal choice but I'd rather have a helmet which will give me more protection on most falls than one that only really does its job on a huge impact. Until someone makes helmets with dilatant liners its always going to be a compromise between a liner that offers good protection on really massive hits but not much on most crashes against one that will give you better protection on most hits but won't do as good a job on massive impacts.