Pros
Good colleague support - I work on the checkout, and learnt far more from colleagues than from very brief, and in my opinion, inadequate "training". Section leaders usually friendly and communicative, and try to be supportive. Job can be interesting as every new customer has different needs and expectations, which greatly alleviates the tedium of the repetitious aspect.
Cons
Low pay, management's focusing on trivia like colour of nail polish to be worn, when daily customers are complaining about length of checkout queues, too many missing items on shelves and not enough checkouts open. Could do with listening more to what customers actually expect from shopping at Asda, and making it easier for them to express opinions, suggestions etc. Also at present very understaffed - especially on selfscan/hybrids - making it potentially easier for theft to go undetected. Inadequate security. Some checkouts too narrow for larger pushchairs, customers with disabilities etc. Being spoken to and treated like children (I don't see the "respect for the individual" much in evidence here)- patronising "training" videos.