The Endeavor was in the middle of the Holiday Rambler line-up, so it was a very good rig at a competitive price. If it was taken care of, it should serve you well.
I believe most were built with the Cummins ISB, which is a satisfactory power plant that you will never wear out. The ISC is larger with more power, and also will never wear out. I'm not that familiar with the gas powered chassis, but friends that have them are happy.
If you really want to talk to some Endeavor owners, locate the Holiday Rambler Recreational Vehicle Club chapter near you and attend a monthly meeting. The club has a web site.