Allen & Heath's hissy? I've had A&H consoles for 6 years now - started with a 16
channel MixWiz, went to a 24 channel GL2200, and just last week got a 32 channel GL4000 and never once have I encountered any hiss. Of course, that is assuming all channel gain structures are properly set as well as any outboard gear. A $100,000 Midas console can have hiss if used with improper gain structure and crappy outboard gear.
I am also not a huge fan of Behringer for the same reasons already given - but as already also stated, you do what you can with what you can afford. Make sure you have the correct channel gain structure set up, use decent EQ's,
compressors, effects units and crossovers/system controllers with the right cabling, and it should work OK - providing the
amps and speakers are also of good quality and you have an isolated AC power source for the system. See where I'm going here? It's not a given that a higher priced console will make your system sound better or that a lower priced unit will make it sound worse. Putting the blame for hiss solely on a sound console is just plain misguided.