The UK generally has one year MBAs, and the US has generally two years. So, other things being equal, you can specialise more in the US. In the UK you could take a one year master of science in marketing followed by a one year MBA, for a lower combined tuition than a US two year MBA. The UK, of course, is more open as a place for foreigners to find work. Maybe Canada or Australia are the best options with both many two year MBAs and more open job markets.

It also depends on your expectations and goals. Most MBA programs everywhere will cover core marketing topics, to a degree. Many go onto successful marketing careers with just a general MBA. But if you're looking for a career where you're focusing on certain aspects of marketing (marketing analytics for instance), then a specialized degree might be more valuable.

In terms of the ease of getting a post-MBA work visa, Canada would probably be the best option. Australia is also a decent choice if you do a 2-year MBA. The UK is always a decent option (if you do your degree from a top school). Singapore (or maybe Hong Kong too?) might also be worth considering, especially if your goal is the FMCG industry.

The US can be tricky. The first year after your MBA, it's usually not a problem because of the OPT visa scheme. But anything longer than that and you'd generally need an H1B visa, for which you'd need employer sponsorship - and those visas are awarded via a lottery system (there are a limited number).