In my opinion, the MBA (in general) will offer a wider variety of options and "backup" opportunities. Even though you have a fairly focussed short and long term plan, things can go awry, you can discover new passions, etc. The MBA degree I think is much more widely recognized in the business world than an MSc. Even though you're looking at an MSc Finance, that degree, while a lot more specific than an MBA, might not communicate its worth as well and and as widely as the MBA.
Through my MBA experience and exposure to finance, I've learned that it can be dangerous to silo up business functions. Even though the traditional organization is: Finance/Accounting Dept., Marketing Dept., HR Dept., etc., ... I think in this increasingly globalized world that every businessperson should have been exposed to most, if not all, business aspects regardless of their concentration. This is why I think an MBA will give you greater flexibility and appreciation for your career.
Of course, you have to then look at each individual program to make that final choice, and see if the program as whole will fit your goals and aspirations.
I'm a current Corporate Residency MBA student at Dalhousie University (Nova Scotia, Canada).
This account is to help spread the word about this unique program, as well as to help provide a student perspective for MBA applications and GMAT experiences.
Every week I publish a blog about life in the CRMBA by interviewing current students. Find us on Twitter and Facebook, or post any questions/comments/concerns in this thread here on gmatclub.com
Highlights of the program include:
Specifically designed by Corporations/Employers, No work experience necessary, 8-month paid corporate residency, Grades/GMAT score not the main focus for admittance