Reputation of Newmar, Spartan, Cummins and Allison are all excellent. At this point with any coach that old, it is more about condition and how it was maintained. If it is in good condition, there is evidence of proper maintenance over the years, and it meets your needs, it might be a great coach for you. I would think you could get it for a great price.
Check tire age, batteries. RV tires age out before they wear out. Most folks will want to replace motorhome tires that are 7 or so years old.
Even though Newmar coaches were made well and had good bones, all the appliances (TV's, fridge, AC units, water heater, furnace) wear out with use. If they full timed, all of the systems got a work out so make sure you consider the cost of replacing things that just wear out. A motorhome is just like a house....something always needs fixing.