This QSC GX 5 is just GREAT, actually I think it is defenitely the BEST poweramp in this price range. It is very easy to use and the flexible input/output possibilities are great as well: for inputs there is jack, XLR and even tulip connectors, for outputs there is a jack/Speakon combination connectors. Even though I don't use it yet, I love the fact that it has a built in 100 Hz crossover that allows me drive a sub and top seperately without an extra device in the rack except for a second QSC GX5 which I'm seriously considering in future.
The amps sounds just great; very clean punchy dynamic sound; nice lows, tight mids, clear highs. The amp's fans are very silent (running idle) and there's no hiss, no noise, no hum; a really quiet amp. We use it every Tuesday at practice and did some indoor and even one outdoor gig with it and it held up very well.
There is PLENTY of power, actually more than we need. Still I would always recommend GX5 with newer Class-H technology over the GX3 that has same weight but less efficient class-D technology. You never know what speakers you'll be buying in future and a little extra power always comes in handy. In practice, we never set the volume higher than halfway. We are a 8-headed rhythm & blues band and we use this power amp in moderate venues to drive a pair of Peavey Eurosys 500 XT subs + Peavey Impulse 200 tops. I had bad experience with DB Technologies active speakers claiming 400W for sub and 200W for tops but almost not loud enough for rehearsal. Now that I know the GX5, I think even the GX3 would be sufficient for our purposes, but as said while the GX5 had the same weight and was only 100 Euro more, we decided to spend 100 bucks on some extra headroom.
For this price, I seriously doubt there's a power amp that beats the GX5 in price/performance. I even think that it might beat much more expensive power amps in power and sound! Highly recommended!