I love Elottronix. It does one thing, Frippertronics, and it does it beautifully. I tend to use it when recording improvised guitar ambient/drone. The "XL" version is nice as well but quite a good deal more complicated.
I've used this a few times. For me it is rather complicated to use. I'll have to look and see if there is a "user's manual" included with the file. I tend to run across cool settings by random experimentation.