Like other members have said it is not the arranger keyboard that makes the difference, but the person playing and programming the arranger.

An arranger keyboard is just a tool for us to be able to make and perform good music. It is up to us as players and performers to know the keyboard and to make the most out of it.

To me, there are two aspects to using an arranger completely: 1. programming sounds and styles and
2. Actually playing the keyboard.

Every time I learn a new song, I then try to see what would be the best way for me to perform the song i.e. do I use an existing style, do I modify an existing style, do I create a new style, do I use a midi file, do I create registrations ….
After I have gotten through that part (programming), I then would spend some time actually playing the song with the style and sounds paying attention to timing when pressing the fill button and when to press the start/stop peddle and so on … I usually think of that as the mechanics of playing the arranger. Kind of like practicing a new classical piece, getting it up to a performance standard.

I think that any arranger that has style making capabilities and sound editing, could last as long as you want it to as long as you are willing to spend the time being creative. If I were to get a new arranger, I would have to still have my old one until I can fully use and master the new arranger.