[Dan Bennett]

Not sure if it applies here, but I had a lot of experience with gauges though in an industrial setting.

The only reason manufacturers ever gave me for choosing liquid filled was to dampen needle flutter if that existed in the system. None of them ever mentioned the gauge being more accurate or being built better.

The comment about temperature affecting liquid viscosity was interesting and could make sense. Unless there's been a major change, the liquid is glycerine which is naturally a pretty thick thing. I've never seen anything about heat ramping for the viscosity but would think it would be much lower than something thin like water.