The Madcap really is one of the most under-rated buggies ever produced in my opinion. I had one from new back in the day and it delivered endless hours of reliable fun. It's a basic design and shares the same gearbox as the Astute. The internal differences being a diy plastic thrust bearing assembly and a plastic motor plate instead of alloy. It's a light and tough car though and performs from the box. Suspension parts are all soft plastics and therefore flexible and tough and the tub style chassis is robust. The front end can get damaged on the chassis but that's about all that is weak on the Madcap. I remember jumping mine off the sea wall some 5 metres onto the hard wet sand below many times without damage (See jump gallery).
I never had the same problems with the diff in the Madcap as the Astute but i'm sure that's only down to using milder motors due to the nature of the Madcap. A few essential upgrades such as the alloy motor plate, ball races and oil filled dampers are a must and make this into a real performer. Capable of taking on any buggy of it's time with ease.