I run one on my 2013 Toyota Tacoma.
Pro:
It gives me about 150 extra miles to a tank full.
Con:
They are expensive.
For Tacomas there is a weird thing with the vent line. I have not been involved with a Jeep install yet.
An FYI:
If you are in California, these are not CARB certified yet. It didn't stop me and I have no regrets getting it. Just something to be aware of.
Edit
Pro:
It fits in the same place as my original tank was.
I do not have to carry fuel containers and have more storage inside for other things.