I understand. Yes, a newer machine is generally better, but some machines age better than others, depending on how they are maintained. I've seen two-year-old cutters that barely operate because of uncleaned filth, wear from lack of simple maintenance, or abuse. Mine is not like that.
Another age-related factor is the design of the machine. Mat cutters, for example, have been improved with every new generation. Sure, the improvements are slight, but sometimes significant. To my knowledge, the 3000 wall cutter design has remained unchanged for a long, long time.
If you could find a newer wall cutter for $500 or less, it would either be incredibly underpriced, or it would have some problems. So long as you can se and evaluate the machine before you buy it, and know what to look for, you should be OK.
Happy shopping!