Generally speaking the hydrostatics are considered better in terms of:
a) going longer without maintenance intervals (5 years by the manufacturer)
b) not going off if they get splashed, or wet, or you go through high humidity
The salt one's however are both cheaper to buy and cheaper to re-arm when it comes time. If you're going to buy one and you don't care too much about price I'd get a hydrostatic one (in fact I did get one
).
Mustang survival makes good stuff. If you're cruising don't forget to get a model with the
harness built in