To try to answer the initial post...

Yes, and no...

Which styles? Every single arranger has got some styles that are better than other's, and some worse. If you narrow down the range of genres, perhaps we could be more specific.

But you ARE comparing a $4000+ arranger with a $1600 one. Build quality, key-bed, weight ( ), sounds and OS differ radically between the two, but styles is a matter of preference, and no two people universally agree on what is 'superior' across the board.

My take on this is that, on the whole, Yamaha's styles are quite complete, whereas Roland's are designed to leave room for you to play. Both sound excellent (I would give the edge in drums to the Roland's, but guitars go to the Yamaha's), but their approach differs. Me, I like to play as much as I can, so the Roland styles work best. Others just want to sing on top, or play a lead line, and the more busy Yamaha styles work better.

But you have to make your own mind up, or at least narrow down your question for this to be more than a cheering section for the arrangers we already have (you'll rarely get a recommendation for an arranger from someone who uses something else!)...