Sorry, I missed your question.
They're all very closely comparable. I've got a Trek 7.3 FX (quite an old one, I've had it about 9 years) and a newish Giant Escape 3 (but non-disc). I like them both, they're both quickish for a non-road bike and they're both equally fun on trails. My Giant does feel lighter and more sprightly but then the Trek was set up as a commuter bike, so it has mudguards and a rack which could be the reason.
Choose any of those three and you can't really go wrong, they're all good bikes. Getting the right size is more key, Giant come up quite big, I'm a large on other makes and only a M/L on Giants. I'm 6 foot.
You asked about the Cannondale Quick 6 and if it was better... well again it's in that bracket, and closely comparable to those. I just really like the colour and the fact that they're less common than a Specialized, so if I had the choice between all these bikes that's what I'd go for. Then the Giant, then the Trek, then the Spesh last.