How bad are factory b-stock electric guitars, because I was looking at in epiphone,
tony Iommi signature g-400.

they're not bad at all.
B stocks just might just have a little nick on the neck or something.
if the problem effects the tone or the playabilty of the guitar, then they can't sell it. thats what i've heard at least. there was a thread on this a few days ago i think.
B-stock is just one that has been returned... or something else that refrains them from being "new".

Get it... if i EVER see my next guitar on B-stock, i'll buy it... like THAT!!!