Unlike a few other of GSi's plugins (read other gsi reviews) this one has absolutely no compatibility issues.  It loaded up great and works great everytime.
I have never referenced the manual and frankly can't ever see myself doing so.  The setup is so simple that the manual will never be necessary.  What you see in the picture above is all you need to know. 
Yes the typical functions are very accessible.


SUITABILITY/PERFORMANCE

I run a Macbook with Logic 9 and Ableton 7.  So far this software works perfectly in both and it sounds fantastic.
The ZD6 has never crashed on me.  I don't think I have made any presets on it so I don't know about preset lose.  It also reacts to my midi board without any problems.
I love this plugin, I give it a 10 out of 10.  It sounds great and plays great.
I have been using this plugin for about 6 months or more.


OVERALL OPINION

GSi does a fantastic job modeling real instruments, and this one is no exception.  What I like the best is the sound that comes out of my laptop thanks to this little plugin.  Its very realistic, very warm and a hell of a lot of fun.
There is nothing I don't like about this plugin.  Sometimes I prefer a different Distortion sound, but all I have to do is instantiate an effect plugin to get it. 
I have been fortunate to have a roomate who owned the same model they modeled the plugin after.  In a few ways, this plugin sounded better (only because his D6 was a little beat up).  Overall though, the real deal did of course sound better, but I was impressed with the quality of the ZD6. 
Logic 9 has a few clavinet plugins, but again, they don't even come close to touching the GSi, or the real deal for that matter.
I paid $100 for this plugin and I am very happy with that price.
I would definitely make this purchase again.