I hope Triad Dude doesn't mind me posting his response to a similar question relating to rear surrounds (7.1) I had within the Triad product line, so here goes nothing...
"I try to avoid LCRs for surrounds because of their limited dispersion pattern and high directivity. If the seating is close to the rear speakers, dipole surrounds will work best; if they're away from the seating, InCeiling Gold/6 Sats would be a great choice at a good price."
The RCS are essentially the LCRs of the Definitive inCeiling line, and the RSS are bipoles. Not sure what the definitive equivalent is of the triad satellites... I think they are monopole designs with wider dispersion than the LCRs... they need a bit of distance to work well as rear surrounds. The debate is pretty fierce with regards to which design works best for surrounds (monopole, bipole, dipole, etc.)... which is why there is a sticky for those that wish to do so (debate).
"A wide screen just makes a bad film twice as bad. "
I wonder what he'd think about 3D IMAX?