Agreed, plenty of advantages to going elsewhere.
As far as the maths course goes, which i presume you're applying to, from your previous posts, then everything is based on your end of year test. because the course is hard, you're less likely to get a high grade in your degree, so are potentially less employable at the end of the degree. Plus, most of the work in the maths course is done away from lectures, on your own, so a lot of it seems to be in a very 'self-teach' kind of method.
Depending on who you are, these might be plusses (they were for me), but then again, most people consider them major bad points. Plenty drop out in the first term/year.