The BK's are definitely a 'set it up in advance' kind of arranger. It's fairly easy with the Favorites and Numerics to call up sounds and styles, but anything deeper than that, you'll want to set up a few Performances with the stuff you want where you want it.
If you liked the G70's touch screen OS, you are out of luck. Another GREAT Roland feature down the drain!
But you still can't beat the BK's for basic rhythm section quality. The drums are the closest to audio drums you are going to find, and the BK-9 ups that department radically. Tons of new kits, amazing percussion kits, just about everything you could ever want, and now for the first time... Ta-da! Fully programmable (and saveable) User Drumkits. Combine any sounds you want into a custom drumkit...
I'll still give a slight edge to the Yamaha's for the Mega guitars, but Roland are inching closer. But bass and drums... IMO, nothing better, right now.
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An arranger is just a tool. What matters is what you build with it..!