I prefer mechanicals myself, and as for leaking, remove that possibility by using copper tubing instead of the plastic tubing supplied with the kit and double checking against leaks where you make the connection. Additionally you should use a rubber grommet or the like when routing the line through the firewall to guard against line chafe.
use both electric and mechanicl .........electric in cab and mechanical under hood with quick connect to check accuracy if need be..........more plumbing but all leaks will be contained outside of passenger cabin.........