I am not sure about other countries. I had done some analysis about going to business school in the US about 7 years ago. Generally, if you have about 5-7 years of experience in the IT field, financially it is not advantageous to do an MBA, unless you get admission to an Ivy school, or your employer pays for it. However, once you reach about 10-15 years of experience, you might find that your growth stagnates in IT. Generally speaking, your career growth in IT accelerates around 5-7 years. You are at a point where you have the skills that a lot of people will hire you, but you aren't that far ahead that you limit your options. Financially, it doesn't make sense to do a switch mid-career.
Of course, a lot depends on what you want to do in life and where your strengths are. If you really want to go into management, then go for an MBA. However, if you are looking at it from a pure financial perspective, stick with IT for 5-10 more years. At least in the US, it's not uncommon for people to start MBA in their late 30s to early 40s, and many schools even welcome it.
Also, if you think you have a good shot at getting into an Ivy school, it;s worth taking the chance. For most people, getting into an Ivy school gives them a chance to completely skip middle management and go straight into upper management, and that is a very very good place to be. Being in middle management is tough, especially for people who are technically inclined