Sounds silly even saying this but, is there a difference between one manufacturers 400W and anothers' 400W?
I have been using a powered mixer for ages rated at 400W per side (all be it a budget brand), and was relatively happy with the sound.
But then I borrowed a friends Studiomaster powered mixer rated at 350W per side (using my own speakers) for a gig last weekend and it had so much more punch and presence (even seemed louder?) to which even the other band members commented.
So is there a difference between budget brand X's 400W and decent brand X's 400W output?