I use one for everything I do... from live band playing with no machines, to full on solo.

Now, I've got other things, too, but I've made arrangers the core of my musical expression for nearly 20 years. However... and this is an important point - choosing the right one for what you want to do is key. In my case, with full band work and playing full(-ish!) piano parts with two hands, I have found that I need a 76. If you have played piano or Rhodes, you know what I mean!

So that takes out Yamaha. They are determined to stay firmly in the 'home keyboard' market (mind you, 'home' players buy more pianos than pros do!) and won't make a 76.

But if your needs don't include playing nearly full piano stuff, a 61 will work.

Next, you might need to prioritize what kind of 'sound' you like. Are you going after a live band type sound, do you want that 'live', on stage sound, or do you prefer politer, more polished CD sounds? If the latter, definitely look long and hard at Yamaha. It's their 'thing'! If the former, Korg and Roland have that wrapped up.

Will you be wanting a very broad range of styles to play with, or do you have certain areas that you prefer? Each arranger seems to do some things best, and asking us here which kind will help, Korg have some really great styles, but of the 'Big 3', they have the poorest selection by the numbers. What they have are great, but both Roland and Yamaha have HUGE selections of styles available, which may help you avoid sounding the same each time...

Overall, unless you are seriously into modern loop and synth music, an arranger is the best keyboard to get for the home (or stage!) use. All the way from nothing but you and a piano sound, to you and a full band, the arranger covers it all. The loop and arp synth/workstations like the Motif's and M3/Kronos/Fantom's, they are great at modern stuff but a total PITA doing anything older, and their accompaniment functions are barebones compared to an arranger.

Keep telling us more... narrow it down and we can give more specific answers.