Before we compare and contrast the Arranger Keyboard with a Keyboard Workstation, the important thing to remember is that the distinction is NOT that one is professional and the other is not. Today, probably the only major difference between a workstation and an arranger is the type of sounds. Arrangers generally have what is known as "bread and butter sounds" (pianos, organ, brass and so on). Where as in addition to basic "bread and butter sounds" a workstation generally has more synth sounds and also better and more effects, as well as other music creation tools too numerous to mention in this context.

In a one-man band situation, both can work to have a full band effect but an arranger would give a more live feeling to the music by the use of intros, fills and variations with in a style. If you get an arranger that allows you to create your own styles, you can make the styles tailored to the type of music you play, and you're playing technique, and with as much live feeling as you need. On a workstation, you can use midi files or program the song with all the different parts and at the gig, play over the sequence. Depending on how you sequence the midi file, you can get a band-like effect.

With respect to composing original music, both an arranger and a workstation can get you to a final original song. On a workstation, you can use the sequencer and record each track in a linear way. Or you can use the pattern chaining function. On an arranger that has a sequencer (which most top end arrangers are coming with), you can also record in a linear way. You can also use the styles to build the song using fills, variation, intros and endings to give the different parts to the song. Depending on the type of keyboard arranger you have, you can either copy or paste the different parts of the styles in to the sequencer or you can record the styles real-time in to the sequencer. When in the sequencer, you can then edit the song to your liking using the punch in recording mode, copying measures and so on. If you don't want to compose a song from scratch, both arrangers and workstations have tools to help you. A workstation has onboard arpeggios and loops while an arranger has onboard styles.

In terms of live performance, and again, depending on the style in which you perform, the advantage of an arranger is the chord recognition feature for performing on the fly, and the vocal processor.

You really have to sit down and ask your self what do you want to do with a keyboard and what would be the best way to accomplish it. Then you can look at workstations vs. arrangers and after that, you have to look at what type/brand of arranger or workstation would best fit your needs.