Robin, I have never heard much ill about FLHTCU or FLHTCUI brakes: they have set a new high in reliability. As every biker can tell you, you do not maintain a scooter like a car: we have to maintain it as one would an aircraft: safety first and comprehensive preflight inspection.
However, if your brakes are always going out, you have doubtless already done the following:
1. Replaced the pads and rotors -- both wheels.
2. Bled the lines (repeatedly).
3. Checked the pressure sensors for leaks.
4. Checked the rear lever for a stripped shaft.
5. Checked the front lever for a loose hinge pin.
6. Checked that the disks and pads are cleaner than a good man's conscience.
7. Checked the pressure integrity of ALL brake system hydraulic lines.
8. Checked the fit and integrity of ALL linkages.
In the 1960's, there was a practice I came to abhor on the old drum brakes: a dab of white grease to prevent squealing. B*A*D move with disks! Usually, normal rainfall will clean them, but if you are always riding dry, give your scooter a heavy wash in a spray-type car wash. Make sure to polish the paint and chrome with bike Silk but NEVER shoot wax on the brakes!
