The best value I know of is the Lesco Z 2. You can get them with a few hundred hours on them for in between 3500 n 4000. They are good for 6899 but even better for 3500 with little hours. For whatever reason they have horrible resale and are exceptible machines that use quality parts.
Ask Envy he is the expert on them and he will tell you they compete with mowers in the 10,000 $ range in operation and quality.