I'm just getting to grips with band in a box. You can write in the chords , chose a length of introduction which it will compose, pick a style and there are hundreds, pick the number of repeats and off you go. Or there are lots of files you can download. It's one click to transpose and I believe it will print lead sheets and chord sheets though I haven't got to that bit yet.
You can hook it up to a midi keyboard, which I haven't yet, and it will compose a melody for your chords or harmonise your one line melody. It seems very versatile and straight forward. Mine is the 2007 version. I may have to upgrade. Around £100 for 2013 version which seems a lot till you consider a book with a cd and 10 tracks is usually around £10 to £12 and you get what you're given.
It's very easy to use once you get into it.