These speakers are amazing! I tried mackies - which sounded thin and distorted at almost any volume, and the ev's - which were much better, but lacked the warmth and character that the qsc's have(especially with the 'deep' switch on).
At lower volume(50%) they sound like very loud studio monitors. I've used them for several very different gigs, with a pub rock band - for vocals and an electric drum kit, they sounded great, with bags of headroom, with the kick drum being heard easily and not cutting out the vocals each time the drummer kicked it!
And with a ceiledh band, with acoustic instruments(violin, mandoline) and electric bass and guitar, where it was very easy to get a warm, rich mix almost immediately.
I can only think of one negative aspect - they only have one side handle, and one top handle - which makes carrying them much harder than having 2 side ones.
So, don't be put off by the plastic build, they're far 'warmer' than the ev's, I'm really pleased with them.
Andertons let me try all their different range of speakers, superb shop, and gave useful, informed advice in helping me choose.