Variation in length of MSc studies
This is not a universal truth, but my experience in researching Master's Programs is that the main difference between a 1year and 2 year Master's program is the research component. 

1 year programs tend to be primarily course based, with a shorter project, if any. Very seldom will there be a 2 year program consisting entirely of classes. Instead, there is usually a thesis, project, essay, etc. that can last around a year. 

No matter how skilled you are, research takes time. So a 1 year Master's program will necessary mean a more shallow project, whereas a two year program alloes for more depth, and is more likely to result in publishable research.

So when choosing a program, ask yourself what you're trying to get out of it. If your main interest is classes, 1 year is fine. If you want to be a researcher or tackle an ambitious project, 2 year will probably be better.