I have to say, one arranger has been all I ever needed. That way, I can devote my time learning the ins and outs of one operating system. I do my best to dig in as deep as possible, and once in a while I have been rewarded by making the instrument sometimes do things no one thought it could do.
I know the Yamaha OS well enough that editing a style, or tweaking a sound is practically second nature, and because it is now easy to do (because of familiarity) I tend to do it far more often, which ultimately enhances everything the instrument produces.
The companies put these tools and features in the instrument for a reason, unfortunately, in my own experience as a clinician, there are very few people who take the time to learn how to use them.
I have a feeling that if they did, they would hang on to an instrument much longer.
Ian
_________________________
Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.