My favorite GB is version 6, the version with Magic GarageBand - it runs on Sierra, so I'm happy. I'm an idiot related to creating music with instruments - I was too busy working on my multiple engineering degrees - but I do know what I like, and Magic GB gives me a great starting point that gets imported into GB v10. I bought MainStage to get at most of the additional content that's included with Logic Pro X - a friend of mine uses Logic Pro X quite often and it's amazing (to me) to watch her work with that app!
I like to use both GB apps when the GF offers to me that it's time to get lost for a while. No, I don't need GB but it's more entertaining then sitting the rain fishing for fish that taste like river bottom, playing golf (ugh), or watching football (on either side of The Pond). My friend has appropriated some of my digital creations and made them sound pretty awesome, so I'm keeping both versions of GB on my Mac! Cheers!