Is this a good Unit and great price for Carrier Gas Furnace?

Turns out I have a bad Secondary Heat Exchanger( original post "Low-Slow Gas Heat" 11-14-14 03:53pm) in the following Furnace. Carrier is responsible for parts and labor for the fix do to a class action suit. 1.Carrier 15-20 years old 2.Model 58MXA06012 I have two options. 1.Carrier will pay all costs to R&R the secondary heat exchanger which should resolve problem. Considerations: It is a 15-20 year old unit. Other than the plastic box that the condensate line connects to (I replaced) we have had no problems with the unit.