Low or high pressure water system

[Scoutmedic]

I want to install a watering system in my run for my 12 chickens (and growing). I've looked at both the low pressure system (cups and nipples) and high pressure system (Little Giant Poultry Fountain). Which one is better for hard water and in the heat?

I've also added a poll to see which water method is more popular.

Thanks for the help!!