The region bosses CP is roughly double of area CP so as a general rule of thumb you want to go to an area with half your CP for a pet. Pets can only use skills (mainly support) and monsters will attack them first proving them to be extremely useful.
My.... last... dying.... wish... is *cough cough*.... with.... more *bleeding from mouth*........ *violent coughing*.... more.... upgrade....poi- *dies*
Goodbye brave truck driver you have shown how far to the right you have gone and we will keep you in hearts as we drive faster with bigger guns, bigger trucks and bigger explosions.