Mo, why would you want anything other than an arranger..Do you really want to develop your own bass lines, and even more important...drums..
It is so much better getting close to want you want with an arranger..You can edit or write your own styles, and use only what works for you.

Once anyone is use to an arranger[and use them to their fullest]..will never want to use a workstation in a live situation [by itself].

Of the two you mentioned, take the Tyros..