I'm tring to work out from TFA whether this is aimed at recruiting new teachers, or developing existing ones. If it's the former, then there have been various similar schemes (or perhaps it's a single often-rebranded scheme) in the UK over the last decade or so. The focus hasn't always been so narrowly on the STEM subjects, but it has tended to be on "difficult" subjects, where recruitment and retention of teachers is usually difficult (and where pupil uptake and performance has been fastest to decline).
In fact, I have a friend who works in teaching who got into it via the scheme in one of its various guises. He's fairly open about both its strengths and drawbacks.
In terms of strengths, he quite openly admits that the salary supplement (which was less than the GBP equivalent of $20,000 when he joined - closer to around $8,000 equivalent) was a very attactive consideration, given that he was graduating with a fair old pile of debt. None of the other career options he was considering would have made it possible for him to move away from the parents and live independently in London quite so quickly. He's also noted that he (and others like him) actually know his subject (maths) to the extent that they can actually field questions from students that go away from the narrow syllabus. He was horrified by how many of his older colleagues were dependant on being allowed to stick to a very narrow syllabus.
On the other side of the coin, a lot of his intake to the graduate scheme dropped out relatively quickly - within the first year in many cases. The scheme was highly focussed on underperforming schools - which largely tend to be those which have the most severe discipline problems. It's no secret that many classes in those schools are more about crowd control than education. As my friend is the oldest of 6 siblings, he came to this with a natural advantage. By contrast, those who had gotten onto the scheme on the basis of academic ability often simply couldn't cope with the levels of misbehaviour, abuse and violence that are endemic in our less impressive schools and dropped out.
The other problem revolved around the reactions of other teachers - and particularly the teaching unions - to the scheme members. This is a profession where pay and career advancement had long been (and is still largely expected to be) determined by length of service, rather than performance or potential. Having a bunch of "bright young things" on additional pay and a fast track to Department-head and other management positions went down in most staff-rooms like a cup of cold sick. At the same time, the unions (membership of which is not mandatory, but is widespread) did everything they legally could to make life unpleasant for them. If you find yourself on a "Fast Track" scheme like this, you need to be prepared to be a bit of a staff room pariah.
So yeah, it's not a bad idea in theory, but expect results in practice to be mixed.