Spoilers often have soapbar pickups, Persuaders are often P-J. Spoiler controls are volume, filter, Q-switch, and PU selector, while Persuaders are volume-volume-filter. I can't tell you much about the sound, but the Spoiler will probably be more versatile as a result of the electronics.
Both are neckthrough-Persuaders more often than not have a nice wood top on them, while Spoilers often do not. The construction is top-notch on both.
IIRC, Spoilers are usually medium scale, and Persuaders can be found in medium and long-scale configurations.
They trade for about the same price, usually between $800 and $1200.