Very cost conscious, and rather rule-bound, sometimes quite counterproductively so — having a 'Wow the customer' motto they then lose the plot and thump staff over really petty rules, which is really demotivating if the reasoning behind the rules is not explained (a common failing).
In practice, the culture reflects the quality of management on a store-by-store basis. One dud supervisor can cause store-wide misery, and the firm does not seem to be very good at addressing this problem when it happens.
This is a very 'no-nonsense' firm — no wasting time, no frills pay (so no paid breaks and minimum pay during holidays) and no excuses for poor attendance, shoddy work and sloppy appearance. On the other hand, my experience is that they appreciate effort and reliability, and can be very accommodating for those who establish a good track record. This comes back to the quality of local management again, so it can be hit-and-miss for a new recruit.
Another plus is that they encourage people to try to progress, and do not seem to hold age against anyone — both older and young workers have an equal chance to go for and get promotion. They value enthusiasm, energy and flexibility, which can come across as being cavalier to anyone expecting a more 'ordered' and 'respectful' approach (although this makes lapses into rigid enforcement of some of their pettier rules difficult to take).
On the whole a very positive company culture, but may disappoint at local level, depending on the competence and leadership of each store manager.
Could not care less