I have it on top of silica sand and am really pleased with it. Stops the sand from freezing or from drying out in summer. It never gets deep and doesn't need much levelling unless you have a big horse with a rider who sticks to the track! I can go several weeks without harrowing but have one friend who destroys it when she rides as she never circles.
The flexiride sticks to droppings so beat to use gloves to pick up. That's probably the most annoying thing about it. My surface has been down about two years and definitely rides better with more use. It needed a LOT of watering when it was put down but none since and as I have it at home with only 3 horses it did take a good few months to compact. It was ok to ride on but definitely gets better with use. Overall very pleased with it. If you are in Surrey I'm happy for you to come see it if that helps.
