The Spoiler has the oval inlays, bird tailpiece and double preamp + Q-switch, those are superior specs compared to the Essence.
(though these days the Essence might also come standard with the double preamp, not sure about that)
IIrc current price of a spoiler is the same as the Rogue.
Bought my first Alembic, a Spoiler in 1981 and it was only 1 of 4 models available in Australia which cost me $1750 so it would have been cheaper in the US at that time.

Wish I could afford any Alembic(or Ken Smith).