Greetings @Bass Man Dan!Hello Rumblers!

The new Stage & Studio Rumbles make your ZOOM sound like petrified dinodookie. I sold my ZOOM B3 right after I received the gift of a Rumble Studio 40. Leaps & Bounds Better.I already use a Zoom B1on pedal, so the built in effects on the 800 might be nice but not really needed.
The Stage 800 has the same Eminence drivers.I kind of like the idea of the 500 with the Eminence speakers.
Don't over think. You need 'em.I'm sure I don't really need the extra watts of the 800.