I think it depends a lot on what you want out of the program, your time and geographic considerations, finances, funding, etc.
One-year programs tend to be more intense and give you less time for electives and research experience, but they also tend to cost less and get you on your way quicker.
Two-year programs are good if you want to build up additional background and research credentials (e.g. for applying to a PhD program without other degrees). They can be nice if you are still getting an idea of the options open to you since you won't have to apply for jobs in your first few months in the program.
Keep in mind that some one-year programs or tracks are only open to people who have extensive experience or higher degrees already, although it varies a lot from school to school.
MSE = materials science engineering? Or something else?
Hope this helps.