Vantaggi
The dogs are (generally) wonderful. You get A LOT of exercise (I averaged 10-13 mile walked per workday). Mostly a pretty flexible environment/they mostly allow you to make your own decisions about how to make your schedule work out on any given day (see exception below). Clients were sometimes very appreciative.
Svantaggi
Employees were/are not allowed there wear gloves in the winter, because it might make their grip on the leash slightly less secure--if it's 15 degrees and windy, I think exposed, frozen fingers are more of a liability than a gloved grip. Sometimes the scheduling demands can be a bit impossible--expecting you to walk over a mile between stops in less than 10 minutes is a little much. When we were understaffed, my managers added about 8 dogs to my route and tried to plan my day for me, but ended up making me pair up dogs that lived far from each other, and end up late to every appointment (which gets a big reprimand from management of it happens too often).