Hey..
I've been working as a make-up artist for a while and alot of people are saying the same thing about that dream matte mousse!!!
I think the problem with it , is that its meant to leave a matte finish.. but then its designed for "normal skin" (which is probably about 1% of all flipping women!!) so doesn't sit properly on your/our skin type!!.. If you're looking for something a little bit cheaper then I really reccomend using rimmel stay matte, or loreal matte cashmere (matte cashmere being my favourite of the two).
Another helpful tip if your skin is dry in places and oily in others, is to mix your foundation with a small pea-sized blob of oil free moisturiser... it really helps it glide over the skin more.. and leaves you with a fresher "glow" about you.. whilst still keeping the "matte" quality there!!
Also, if your applying your powder with the little "powder puff" thing you get free with it, then I'd invest in a powder brush (body shop do some amazing ones.. cheap.. but nearly the same quality as the ones from MAC woohooo!!).. doing it with the powder full makes it more cakey and visible on the surface of the skin.. it also really blocks pores.. before i knew this tip you should have seen the blackhads *shakes head with shame*..
if you use a brush and lightly tap/brush it on the areas you need it you'll stay shine free and fabulous!!!
hope this helps!! :oD