both got pro and cons...
from wat i see....i am now in matriculation programme
here i meet a lot of sbp and mrsm student...
here some story i heard from them

if ur in mrsm:
>u will have plenty of oppurtunity to join fast track programme
>u might get sponsor by mara to oversea if u are g00d enuff

if ur in sbp:
>i dunno...

i dunno what to say
i have friend in mrsm now doing fast track at UTM
and another friend from sbp sains seremben now got jpa scholar
doing preparation to go to korea
so both good choice....