David,
We got our wheel clamp, a Bulldog QD, after reading it came out tops in a security test in which several wheel clamps were tested. It's fairly straightforward to put on and take off too. The only thing we found was that it was not brightly painted and to make it more 'visible' we got a can of day-glow yellow Hammerite and sprayed it.
Most insurance companies now insist on a wheel clamp and hitch lock as a minimum requirement. Some do offer a discount, but not all.