Pros
As stated in the title, it's very interesting learning the work of a vendor if you've never had prior experience in the field. The flexibility is wonderful, perfect if you are going to school, work another job, or have a busy home life. You won't have any problems with getting bored, because you're consistently multitasking throughout each store, so it definitely helps to pass the time. As a side note, the majority of the time, I personally loved helping the customers in the stores I worked whenever possible, although that is not in the job description whatsoever. I quite often received compliments that I out-performed the employees of the stores I was in vis-a-vis actually showing an interest in helping customers.
Cons
The negative side to consistently multitasking, is the fact that you literally trek from one side of a store to the next, then back to the one side, and back again to the other to finish terribly planned-out activities. Lather, rinse, repeat. Even if you plan your route accordingly, there will always be a random, unexpected part of an activity, or entire activity, to surely throw a wrench in your perfectly-schemed schedule. The negative aspects of each store's customers is that they constantly mistake you for a store employee and expect you to solve every single problem and answer every single question they present you with, even after informing them, often multiple times, that you are indeed not an employee of the store and are solely just a vendor trying to get your own grocery list of work activities taken care of within the slight amount of alotted part-time hours given per day. It's also very difficult, most of the time, getting the cooperation of a store's employees and management to help with projects that their own home office have created and expect to be fulfilled. It is almost an everyday struggle fighting through the aisles and boxes and asides of boxes in the back storeroom just trying to get to and from your bin for supplies and materials through the day, then throw in the fun of going on a wild goose chase to hunt down misplaced Anderson boxes that could be pretty much anywhere. Even after continuous communication with the help desk to fix the issue, the mods were horribly inaccurate in at least half of the stores that I worked, in relation to the actual shelving space and the massive quantity of stock that was expected to fit in the often miniscule area. Add in the multitude of mandatory no-return items, and you are left with a complete quagmire of a problem that has no "officially acceptable" solution. Store employees have an odd way of wanting to do your job (more like completely botch it) while you're not there, yet stand around chatting with each other, texting, and taking breaks/lunches at the same time so that when you're the only person in a department for endless amounts of time, you're inadvertently the go-to for any and all customer inquiries and complaint, or you're stuck waiting ages to complete your activities because you need an employee for this or that.