Things were changed up a little bit with the JJ Custom, and I'm not entirely sure why. It might have had to do something with copyright issues, or it might have just been Scott Ian's own personal tastes. Regardless, there are a few things that make the JJ Custom a bit different. One of them is that the body is thinner than the other ones. The headstock is also a little different. I'm going by memory, so forgive me if some of these stats are wrong. The guitar features a mahogany body, either a mahogany or maple neck (I forget), a rosewood fretboard with a unique fretboard inlay on the 12th fret, a hard tail bridge, special paint job, one humbucker, one volume and one tone.
This was pretty much your no-nonsense guitar. You have one humbucker in the bridge, an old school flame hot rod paint job, hard tail bridge and that's about it. It's meant for those who just want to rock, really. The guitar was put together fairly well. The nut needed to be either reshaped or replaced from the wear. Actually, I think somebody might have filed it to accept really thick strings, or somebody just started filing it for no reason at all. Regardless, a nut replacement was needed on this due to some sort of wear and tear. The neck felt real nice, and the finish was still holding up after all these years without much of an issue.
This is pretty much a no nonsense guitar. The guitar had the Scott Ian pickup installed in it, and it was a fire breathing monster. The thing had tons of output for super aggressive rhythm sounds. You could put this through a stock boosted marshall, and you'd instantly get that old school thrash sound without any issues at all. It cleaned up decently once you started rolling down the volume, but it's not exactly the most versatile pickup in the world. One thing with these guitars is that I always find myself missing the neck pickup. As a lead player, I tend to rely on the neck pickup for leads, so that was slightly disappointing.
The guitar is very solid, and despite the changes that occurred, it's still a very solid guitar. You'll want to search for these on either eBay or different forums for the best deal. I wouldn't recommend trying to look for one in the stores.