We had a 2002 Dolphin LX for 5 years - the model 6356 LX. Had numerous small problems in the first year but eventually got them all cleared up and it was pretty solid after that. Our only real complaint was a pervasive dampness in the bedroom area whenever it was chilly. It was probably damp in warm weather too, but we didn't notice it so much then. We had the Workhorse chassis version, which has much larger storage bays and greater CCC than the Ford chassis version in that year.
Overall I feel it was a decent coach, but with any coach that is 13 years old, any original issues are water over the dam and the current condition is all that is really important.
I recall that the 2002 Dolphins didn't have an automatic transfer switch to shift to generator power - you had to plug the shore cord into the genset outlet to use the generator. Not a real big deal, but a bit unusual for a top-of-the-line gas coach. Later models added the ATS.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL