I have and also used to have several other high end acoustics - current ones have BRW back and sides or English walnut back and sides
Have had several IRW guitars
Anyway I reckon that the back and sides wood counts for about 10% of the tone the top being far more important. However, sometimes you get a combination where that 10% of BRW really does sound marvelous.
My favourite combination is Engelmann spruce top, BRW back and sides

PS - the player makes quite a big difference too!