Vantaggi
If you are a temp they can be very accommodating and you'll get a lot of work if you want it, if you say no to one shift don't be surprised if they don't offer you much. If your face fits the company you will go far even if your not right or experienced enough to really be right for the position.
Svantaggi
They seem to have a training system that breeds terrible managers, I know it sounds like I'm disgruntled but I've worked in three different shops as I've moved round the country, had some great managers, team leaders etc. yet I've also had managers that insult people, gaslight staff, go out their way to destroy confidence and upper management do next to nothing to help resolve situations. I've complained about manager treatment in the past and they just brushed it off as it doesn't matter they have transferred to a different store location. My confidence has gone up and down more than a yo-yo. Why haven't I left? well because I was strung along promised development that has never come, been told you need to this to develop (did it) then told no you need to do this (did it as they said) no you need to this way you've done it wrong (I did it like they told me to do it)> but yeah really depends on which shop you work at really and if your face fits the company.