Bud, there could be, and should be a book just on Multi Riff alone. It is similar to how you generate, cut and past multiple tracks merging the edits into a unique single track. But that does not equal to Multi Riff capabilities.
Multi Riff is capable of constructing a riff from a note to the whole track. It will give 7 selections and the user can choose to select one, more than one or all 7 Multi Riff versions. If more than one riff is selected, the user can select the tracks where the additional tracks will be placed. Riff generations are user selectable to begin earlier and end later than the highlighted selection allowing a higher quality merge between the newly generated audio and the track audio.
You have two choices with every Multi Riff selection to either generate the current instrument or to choose any different RealTrack in the database. That means if you had used all of the available 48 tracks and needed room for a Bridge solo, you can use Multi Riff to generate and insert your solo on any existing track to do so.
On my system, generating a Multi Riff also generates a Midi Real Chart for the generated audio. A Midi instrument or Super Midi instrument can use the chart to twin with the Multi Riff generated audio. The Midi Real Charts can be erased and discarded if there is no need for them in your song.
If you are not satisfied with a bar or two of your chord chart, you have a choice to select and regenerate the RB track as normal or you can choose to generate 7 versions with Multi Riff to give yourself additional choices.
You get a lot of choices in the way you generate multiple tracks now. If you had the Multi Riff feature, you could save time and have better focus by being able to hone into the specific area you are wanting to work with. Also, if you are generating 7 track or 8 tracks to comp a solo for 8 bars, you have many choices if the generated tracks share additional verses or chorus's with the area you are working in. If they don't, say you are working on a bridge and it uses chords specific to the bridge, then without further time spent generating additional tracks, you are limited to the 7-8 tracks. With Multi Riff, you can generate a series of 7 multi Riffs in probably a 1/4 of the time it takes to load and generate complete tracks.
Again using an 8 bar uniquely chorded bridge, the seven different Multi Riffs can be cut/pasted into a unique bridge from the 7 selections.
I've probably overlooked things but that is a short summary. I'll leave with the thought that a year or so ago, I gifted the Pastor of the Church I attend a BIAB program. He uses the Mac platform and requested the Mac Biab version. I gave him a RB and Multi Riff demonstration and he purchased a PC desktop for his music and got the PC version of Biab.
Hopes this helps. If I've overlooked features or you have questions, post them here and either I or another user will try to help you out.
If you are wondering if it's worth the investment of a PC based desktop or laptop, I think it is.
Charlie