IMHO, an isolated second battery whether in a standard dual setup or in an aftermarket portable solution like the National Luna Portable Power Pack will give you the most reliability and maximum power to get you back up and running if you completely kill your starter battery.
The jump packs are good if you've only run the starter battery down, but if you manage to totally kill it, most of them I've used won;t bring you back to life.
I have the National Luna PPP in the back of our Suburban and have been very happy with it.
04 Audi allroad
03 Chevy Suburban
SOLD 05 Subaru Outback
"99% of being smart is knowing what you're dumb at"