There's some pretty significant differences in the way you work an arranger compared to a loop and arp playing WS. Now, I haven't played the XF yet, but the XS had VERY limited arp playing options.

First on the list - you had to manually select the loop you wanted... OK, maybe some of you are used to doing that, but arranger players have it a bit easy. When you press Fill, what is ACTUALLY happening is that the fill pattern drops in IMMEDIATELY (usually) into the currently playing pattern, then, when the fill is over, it then goes automatically goes to ANOTHER pattern (or the same one if Fill-to-Same is pressed). But on an XS, you have to do ALL those different things yourself, all in realtime

Now think about what Intros and Endings do... one plays fully, then goes automatically to another loop, and the other plays, then automatically stops.

That's a LOT of things being done for you on an arranger, that you don't get on a WS (AFAIK). So be careful calling them 'styles'