This is about the only leap of faith I have made with a keyboard. Normally, I want to play anything a couple of days to make sure I can't live without it...
But I do have a BK-7m, so quite a bit of the overall workflow and basic sound is familiar to me, and a lot of the styles. So I'm not flying quite as blind as it might seem.
It always pays to take a USB stick to a dealers. If their software isn't up to date, most things upgrade from a stick, nowadays, would have taken you 5-10 minutes to upgrade the store keyboard and then connect to the apps. I think, with how barebones brick and mortar music stores have to be to compete with online sources, that yes, it IS too much to expect all their gear to be upgraded..! YOU probably know ten times as much about the arrangers than any in store personnel!
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An arranger is just a tool. What matters is what you build with it..!