I power on my a4000 every few months now and each time I'm amazed at the awesomeness of it. It's extremely flexible but you have to read the manual. When you take the time to make good patches, assign controllers and use it as an instrument, it will do wonders. Great as part of a "modular" sort of rig where you can patch other signal processors over it.

I used to play live with two of them in my rig (till they got replaced with ableton), really great sound over a big pa which unfortunately ableton doesnt compare to :(. I Also use them as a standalone midi synced efx unit. Nice wide delays and plenty of depth that I just can't get out of the computer alone. A few fancy efx too.

To cut it short, you get out of it what you put in. Give it some love and a lot of time and it'll excite you in special ways ;)