Well, let me say a couple of things.
People with MS in Math or any other quantitative discipline can find a job in finance, and I know several people who happen to work in finance or were offered jobs in finance having MS in Math, Stats, OR.
There are two points here that need to be stressed.
(1) There is a higher chance that you find a job in finance with MFE than with MS in Math.
(2) If you want a job in finance, why going for MS in Math? That is, why would you spend time and efforts taking Topology, Differential Geometry and some other courses that you would not use, if instead you could take courses in disciplines that you are more likely to use at work.
One more point is that companies know what MFE is and they sometimes prefer to hire people who already know something about finance.
On the other hand, if you get an MS in Math from one of the top schools, I think you'll have good chances of getting a job in finance.