I've got one on one of my cars and have found it ok but like all electrical / battery contacts it does need to be kept clean and corrosion free. I like to keep my battery terminals smeared in petroleum jelly or that red ant corrosion gel anyway.
There is a battery isolator / anti theft device that fits on the battery + terminal and has a knob which when removed disconnects the battery. There is a version whish has a fused low current permanent supply for radios etc too.
I have one of those but found it quite disappointing. The vehicle now sports a pair of ex fire engine two tone airhorns with the two tone valve disc removed so both horns sound at the same time ....they're much more effective
Having been on SORN for the past seven months while I was too bone idle / busy doing other things to finish busy converting the overcab area into a bed I finally got around to getting around to submitting
for an MoT yesterday as the old one had expired the back end of December.
There is little to touch the warm glow that comes with brand new pass certificate is there?