I currently have:
(and my since departed first Ibanez, S540LTD in DSY)
They each have their own distinctive characteristics. The 2020 has the chubby neck, the other Wizards. The 2540 and 2020 come close on classiness, but something about the older 540 that feels and sounds nice. I agree with rgshred on the IBZ/USA Dimarzio-made pups.
As far as the 2020 vs. 1540...the neck shape difference and binding/rosewood head stock veneer on the 1540 are basically what sets them apart (except the piezo, of course). IMHO neck shape is a biggy here.
If i could order any I wanted?? Dream a little? I'd place an order from Ishibashi for the neck through/quilted maple JC.