Yep, quality trumps everything everytime. The thing with using only one speakers is that you will have to turn it up to be heard farther away in which case it gets too loud close to the speaker (the infamous “speaker bubble” where nobody wants to stand/dance). So utitilising more (2 minimum but 4 works real well also) speakers means you can get a better overall sound level without having to push the individual speakers too much.
Apart from the less than optimal bass in 8″ (anything under 12″ really) speakers, I find that 4 well placed 8″ speakers (preferably with 1 or 2 subs) CAN potentially give you a better, more even sound than two 12″ up front (depending a bit on the shape and size of a venue of course). Another bonus, sometimes, is that the 4 speakers when set in a square facing each other is that it more or less “forces” a dance floor. And for some reason it seems easier to get people to dance when their is a proper dance floor “area” (at least for the kind of gigs I do, some dance bars don’t have a dance area and people just have at it wherever they are standing :-).
So, even if I don’t need it sound level wise, I will still often set up a second set of active speakers to define the dance area (so not having them face further down the venue, but back towards the DJ).
Just my two cents.
Greetinx,
C.