One thing to keep in mind is that many style are already tranferred/transposed into the other keyboard makes. For instance, many Roland G70 styles have been converted for use with the Yamaha PSR series. And many Yamaha styles have been edited to work with Korg and Roland. Additionally, most mid to upper level arrangers have the means to do this editing yourself, if you become so inclined.

Have you considered the possible use of software based arranging such as Band In A Box or One Man Band? There are a few others that permit you to pre-select chords and choose from a vast library of rhythms. The outlay for BIAB is reasonable and you have way more style to choose from than a hardware arranger.

Otherwise, watch out for those of us who proclaim that manufacturer A,B or C is the BEST. It's only the best if it is right for you. Lastly, you do not necessarily have to have the most expensive model to get all of the good arranger styles, just don't buy the entry model - you'lll be sorry.