It depends on your needs. I use the AN1X and one module-an EMU
Vintage Keys. The AN1X knobs can send CC data so you can set a knob
for breath control and turn down the external sound module and turn
up the AN1X at the same time. This is useful for playing organ then
switching over to a lead synth sound.
I try to make sure the arpegiator is off on all the AN1X presets,
otherwise I get these cheesy patterns playing through my external
modules.
If you have a complicated set up, you need a more elaborate
controller.
Rainbow Jimmy
http://www.mp3.com/spaceanimals