I think the hydraulic system is excellent if well maintained. As with anything old, this is a high pressure system and everything needs to be tip top, any weak spot will be exposed with p!ssing fluid! In the Bora, it controls more than just the suspension, even the pedal box is hydraulically adjusted. So if it fails, its probably a total failure and time to call the tow truck.
It probably the sort of think that would let you down on a long trip and leave you stranded, hence the unreliability, but Bal should be able to give a full account, hopefully not from experience!