The configuration of the Farfisa Compact Professional takes some time to get fully used to, as there are a lot of parameters to adjust your tone. Once you play with it a bit, it is easy to understand all of the functions as they are smartly laid out and everything is easy to access. Being that this is a fairly old instrument, I don't have a manual for it so I can't speak to if it is helpful when trying to learn this or not.
The sound of the Farfisa Compact Professional I organ is pretty specified, but is suitable for all types of music if you want to get creative with it. This organ will give you the type of organ sound that has been made famous by Elvis Costello and other artists with a similar style. It is kind of a cheesy sound, but this cheesiness is a lot of the reason it is so popular. It is overall a unique sounding organ that sounds pretty different from what you would think of as your traditional Hammond organ sound.
I've been using the Farfisa Compact Professional I organ for about two years and I really love the sounds I get with this. I'm a huge Elvis Costello fan, so naturally I would like the sound of a Farfisa, but this keyboard really is versatile and has an overall awesome tone quality. These are somewhat rare, so the price isn't all that cheap and I would really only recommend this to those who really want the real deal in terms of a compact organ sound. Overall, a classic instrument that is completely unique to itself.