Tried it over the weekend and treated the whole interior with it (except steering wheel). I have sand'ette btw.
I have been using Vinylex before. I have to say I like the BM SG better than Vinylex.
It has a lower gloss than Vinylex and gives a natural look to the dash/door panel/seats. Color seems a little darker and deeper.
Best of all, it cost me $2 a bottle at Pepboys. It is on clearence now think. I never tried 303 but this is a good alternative. It contains PDMS(PolyDimethylSilicone, the good silicone) and is water based just like Vinylex and 303.