What are they like? Any significant difference than a regular guitar neck?
Well, they are bigger. Longer neck. Made for low tunings.
there in-between a guitar and a bass...simple ass.
I think the jaguar is a barritone, well at least it was when I tried it. It's got bassy strings, not your average strat or tele.
by in between, he means size wise. when you play one it doesn't really feel like a bass at all.
I have a baritone guitar, it is larger, longer neck, somewhat a mix of a bass and guitar, more strings slack, more chunky, especially when palm muted, thicker strings, harder to make it scream, more 'macho'