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I'm a bit confused as to exactly which amp you are asking about. Is it the now 1½ year-old Rumble Stage 800 bass modeling combo, or the now 6 month-old Rumble 800 HD head without modeling?
While somewhat similar, they can be quite different, too, though your title of "next step" could apply to either one. The HD is a next step, at least for Rumble amps, as a high power, 2 ohm capable head, and for having a Pre/Post switch for the XLR Out, and Speakon connectors, but still having analog settings. The Stage is a next step for bass amps in general with it's digital modeling features in a high power combo and, although it, too, has a Speakon connector for extension cab(s), it is "only" 2.67 ohm stable.
I've had a Rumble 500 combo, which weighs about the same as the Stage for over 4 years. Have loved every minute of it. But, I was fascinated with the Stage 800 & Studio 40, and their identical operation, since their introduction. Finally, I got the Studio 40 a few months ago, realizing that I can chain the Studio thru the 500 to amplify the modeled tones almost as loud as the Stage.
You're welcome to visit and question
The Rumble Club to help make your decision. And peruse the Rumble Wiki page, linked in my signature, for all kinds of Rumble information.
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