I'd definitely say that, if you've got an iPad, getting Koala sampler FIRST and finding out if modern beat creation is your cup of tea is the way to go...
It's a COMPLETELY different way of creating a backing to an arranger, it might not float your boat. Trying the idea out without purchasing hardware first seems the way to go unless you're already familiar with MPC workflow...
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An arranger is just a tool. What matters is what you build with it..!