The electric I played was one of their older thee-octave-neck models (I no longer remember what the model number was). But this puppy was nothing short of AMAZING. Can you imagine the edge of your neck running seamlessly almost all the way up to your bridge-position pickup?? This is how the neck felt to me!! Clearly, it was an instrument built for speed and access to the upper frets.
But as impressive as it was, the upper-fret access was just about as frustrating as it was astounding. At least it was to ME. Those of us who have big hands have probably never imagined what would happen to fret spacing when you get up past the 22-24th fret!
Can you imagine having an entire octave of frets squeezed into a mere 3.125"?? Talk about NARROW fret spacing. My big mitts couldn't come CLOSE to fretting the notes with any acuracy. However, I did have a much easier time locating the "nodes" for upper-fret artificial harmonics (which I use somewhat regularly in my own playing). Having frets all the way up into the third octave makes it much easier to find the 8va points on your first try.
So though I didn't find the extra octave to be much use beyond providing clear placemarkers for harmonics, that shouldn't turn you away outright from such an instrument if you want greater range in your playing. Those of you who aren't burdened with big fat mits for hands will find the Stephen's Extended Cutaway