Caution-read what Finals 3 Greens said very carefully.An MSc is a huge consumer of time and effort,it can destroy your social/family life (I did mine on a part time basis over five years).
The nature of an MSc can vary widely.I once saw a thesis on "The Mating Habits Of Wide Bodied Midges".This is the kind of stuff which gets academics a bad name.
Someone once told me that for an MSc you learn more and more about less and less until you know absolutely everything about f*#k all.
Choose your course carefully!