The Gibraltar Encyclopedia of Progressive Rock (
www.gepr.net) defines it as: "symphonic rock done in a typically more simple or commercial format. Also very lush but lacking the complexity of the symphonic bands." This defintion works pretty well for me, but I also feel that most neo-prog bands emphasize a highly-synthesized and highly-produced sound. Whereas many symphonic bands can usually reproduce their sound on stage with the same type of precision as in the studio, I assume (and I am only guessing here) that many neo-prog bands would sound less polished on stage; the definitive version of their music will usually be the studio version.
I can usually distinguish between neo-prog and symphonic prog by listening to the keyboards. Neo-prog keys are the main focal point of the music almost all the time; they get all the hooks and all the memorable melodies. They also tend to be always synthesized; very little piano or Mellotron in neo-prog. This type of keyboard empahsis can be seen in bands like IQ, Jadis, Galleon, Arena, Pendragon, etc.
For the lesser knowns:
1. Somnambulist - "The Paranormal Humidor"
2. Citizen Cain - "Serpents In Camouflage"
3. Van Der Graaf Generator - "H To He, Who Am The Only One"
4. Wishbone Ash - "Argus"
5. Galleon - "Beyond Dreams"