In all fairness i have never tried one of the mt2's (i dont think) but i really cant fault a saint, on my 24 i'm running one of a 200mm rotor and cant fault it, changed the pads recently to better ones and its almost too powerful believe it or not..
Also ran it on the rear of a mod (leaking, contaminated) on a 160mm rotor and still couldn't fault it performance wise, the leak wasn't awesome though haha.
If money is a problem go for the mt2 as they seem great for the price haven't heard a bad thing about them, but if it isn't then without a doubt, get the saint.