I like Synflex, it's expensive but has a lot of advantages over steel-braided hose. It doesn't break down over time, it makes the pressure at the gun seem smoother, in an emergency you can splice it with a barb and clamps (I've actually had repairs like that last for years). Downsides is mainly cost, it's more than twice as much as Neptune 3000 hose, it has to be protected from rubbing on anything hard or sharp, and even though it can withstand being frozen it may cause a micro-leak under the sheath.