Well, the custom-s has the sustainiac pickup in the neck position instead of a similar humbucker that’s in the bridge position. I’d ask yourself “how often will I REALLY use the sustainiac?” because you may end up spending $600 or $800, or whatever difference, too much to just use it for the few songs that use it. If you don’t use Sustainiac in your own playing and improvising, I wouldn’t spend the extra. However, it’s very cool to just have it so
I’d really dive into yourself about it first.