For years 2005-2009 the top three, Signature, Executive and Dynasty were considered "Luxury" coaches. They were built with a steel cage as opposed to the next models which were constructed of an aluminum allow framework. Later, the Executive model was dropped and the Camelot was elevated to the luxury level below the Dynasty. The Signature was always the top of the line. What we found when looking was all three were built basically the same. What was an "option" on the Dynasty was standard on the Signature, etc.
I would not hesitate to search for a well taken care of 05-09 top tier coach. The MSRP on my coach was $585,900. These can now be picked up for about a third of that. They're well made and the fit and finish are excellent. We have the 10 bag system which are all outside the frame rails. This gives you excellent ride and handling. Only negative on our coach was the Norcold which we've replaced.....Dennis