Well St. Gallen is very very well known for its Msc in Strategy & International Management and is holding up the No.1 position for quite a number of years, even in the 2015 MiM rankings it still holds the No.1 position. So the school is really working hard to stay at top and keep its quality of education high.
I have a few friends at St.Gallen who really recommend the school as its quality of education and the post grad opportunities are really top class.
Not really sure about the Master of Arts in Accounting and Finance degree, but if its anything like the Msc in strategy, then take it without hesitation.
Bocconi is an excellent school on its own, but then it kind of pales in comparison with St Gallen.
Also the italian economy is not in a super good position, so i guess St Gallen is a better option.
But then again Bocconi has an excellent reputation and is recognized all over europe too, hence you have a good chance to get a job elsewhere.
Both are excellent choices, but i would put my money on St. Gallen.
For people who want to know if they have a shot at any of these top MiM schools, i would suggest getting your profile evaluated at
https://mim-essay.com/profile-evaluation?gcfIts a good way to see, where you stand among competition.