Pros
Xiaomi makes great products so there is a lot of potential for great marketing. There are a lot of good talent at all levels - people are good, at least when they come in to the system.
Cons
Specifically about marketing, there are people who work here who frankly appear to have no clue about marketing. They think that dressing up and talking smoothly about the product on stage or on camera is marketing. Incidentally there is a large group of such people who tend to act like they are annoying rich kids in school who think they own the place. The problem stems from the leadership and the favouritism this group enjoys with this leader. With the team split between newer employees who come from the real world, and this delusional group of insiders who suck up to their leader, the resulting confusion with random decisions taken with no good reason are causing chaos. Its a terrible work environment where you will lose all interest in doing good work because only those who suck up to the boss get awards and also get promoted. Your chances of getting recognition are only as good as how good you can suck up.