Glad to hear they're taking care of it for you. I just worked on an FT-101A that was approximately 3-4 years old (which has the same guts as the current MD-100), and the circuit board was delaminating, with a few traces oxidized and falling off the board. Yikes!
Beyond that, the basic engineering and design was essentially a mid rank car radio. Fortunately, with some careful parts replacement it can be improved over 500% and often more in terms of measurable distortion performance without adversely affecting the tuner in any way. Neat. This tends to occur across the line, based upon what Magnum told me about the design of the other tuners, although the TOTL 108 might be a different IF and decoder design. I didn't ask them about that one.
The roof mount Yagi is definitely the way for pulling stations, and with a few grand into the tuner, you owe it to yourself!