I don't know if one type of valve is more prone to leak-down than the other, but all hydraulic apparatus can do so over time, particularly as they get worn from use. Many, if not most, old Fords, Fergusons, etc. from long ago, eventually had 3 point position control lifts that leaked down and needed rebuilding. As a practical matter, you usually need to tweak the settings periodically anyhow to compensate for uneven ground conditions, so a circuit that leaks down over 30 minutes to an hour really doesn't affect how you use it. When a rock steady position is required, you typically find some kind of check circuit on the hydraulic cylinders.