I know Peter already recommended people to apply to an MBA program rather than the MiF. I hope he is impartial although it is always good for schools to improve their yields...
However, given that I am not clear about your experience and scores, it would be hard to judge the suitability of Peter's answers. I personally had 3.5 years experience prior to joining the MiF and I know some people with as little as 2 years only so it's a case by case basis. Less experience means you'll obviously have to compensate with a higher GMAT/GPA.
Bear in mind that the MiF will provide you with the SAME job opportunities that the MBA will. If you are looking for an alternative to an MBA, a finance focused program, then go for the MiF. Otherwise, if you are looking for a stepping stone to an H/S/W MBA which you will accomplish later on, do not apply to the MiF. I also once thought that I would have liked to do an MSc kind of program first before applying to an IVY league school but once I learned more about the MiF, I let go of that idea. Furthermore, living a year in London and paying 30k sterling for your tuition will probably discourage you from that MiF/MBA path.
While you will have to put up with a lower post graduation salary following regular MSc programs, it will be a more logical move to do that first and then an MBA. Doing a MiF, or an MBA equivalent degree, and then go back to do an MBA to graduate with a similar post MiF salary but only 3-4 years down the road is not the best option IMO.