I have a few thoughts to throw in on this Dan, mainly about Real Band. Just my own views though, and others may see it differently.
I think the old Band-in-a-box (or BIAB) that we've all seen at some point in the past is technically impressive but not very interesting as a serious music generator. That's mainly because everything is midi driven and the end result sounds like the jazzy demo tracks on inexpensive home keyboards.
PG Music must have recognised this several years ago when they started to offer Real Band (or RB) as a separate similar program along with BIAB, and it is far more sonically impressive. Many of us like software such as EZdrummer that generates complete parts using real drum sounds, and many of us like using loops (as phrases) in our compositions. RB does both of those things.
I never use BIAB. I don't use RB much now either, but I have done in the past and have a few tracks signed to a library that were generated partly or wholly by it. The big advantage is that RB can use audio phrases of real instruments that were played by really good musicians. Who'd turn down Brent Mason if he wanted to play a bit of guitar for you? He's in there (amongst many other good players) for a few styles of real tracks!
Just like BIAB, all you need to do is type in the chords into RB, pick a style, and click 'generate'. As has been said, editing the results to sound like a proper performance might then take some effort, but that can be a whole lot easier than working from scratch, especially if you have no players, instruments or skill. I've sometimes generated several versions of say, a lead track, then flipped back and forth between those version to get the best result, and sometimes swapped out the drum track for a better one. I've also generated a real drum track on its own to fit something else I was working on, and that's very easy (all you need input is the structure and style without caring what the chords are).
I think it will always be hard for BIAB to escape its past reputation for cheesy jazz and sadly that also affects RB, yet you can just as easily generate a very passable Stevie-Ray Vaughan style blues guitar track with RB. I have done, and a library signed it
. What if you wanted a small jazz combo track, then also wanted a big band version of the same piece (chord-wise) at a different tempo and key? Its quite possible to do such things with a few clicks and have the sound of real instruments as phrases played by real musicians. I can't think of any other tool that would do this more easily, or would make a better job of it. If thats how you want to work then its a fine piece of software. Anyone who hasn't got the foggiest idea about chord structures will find both BIAB and RB an uphill battle. Anyone who wants to lay down some hip-hop beats, or experimental ambient textures, or who is more focused on recording and/or using VIs would probably be better off looking elsewhere. That's not its forte.
Negatives? PG Music offer a bewildering array of versions of the BIAB/RB combo that include some proportion of all the available add-ons (midi tracks, real tracks, etc), and always have some impossible to refuse additional offer on top of that if you're willing to pay just a bit more. It can get pricey to buy the lot, although you do get a lot for your money even if you'll never use about 75% of it. Styles are expanding across genres, and you often have to get a whole mix of stuff you don't want in order to get a good offer on the stuff you do want. Of course, everything gets updated every year, and for a bit more money again you can upgrade to get the latest features that you can't possibly live without, then pay a bit more on top of that yet again to get all the latest add-ons and tracks, etc. They're not alone in doing these things though - its modern marketing!
After many years, I still think the BIAB and RB interfaces (which are very similar) look like they need a pro make-over and there are some quirky features, but I don't recall either program crashing on me. They don't stand comparison with any fully-fledged DAW (and you wouldn't expect that for the price), but its easy enough to export tracks and pull them into your DAW afterwards if needed. Finally, I'm not sure whether there's a 64-bit version on offer yet, but I might be wrong.
In summary, I remain open-minded about RB. Horses for courses and all that, but I've not been on that course for a while