Re: body joint and sustain?
"So, Bollocks is bad, but Dogs Bollocks is good?"
"Yeah mate."
-Formula41
Dogs lick their bollocks, ergo, they must be good (to the dog, at least), so "the dog's bollocks" is akin to "the cat's a$$" (which follows the same logic). "Bollocks" is not good, hence "Nevermind the bollocks, here's the Sex Pistols".
As for the topic at hand, a poorly-made body where there is a joint between any 2 pieces at the center is the same quality as a poorly-made 1 piece body or a poorly-made 5-piece body whose joints surround the neck joint evenly. Crap R crap.
I'd be more concerned with how the base of the neck pocket and the bottom face of the neck heel meet, as I've seen some poorly-cut pockets that had a smooth rear wall sound like utter crap, but a guitar that had a slight gap between the rear wall and the heel edge but a smooth heel face and pocket base sounded better.