THe multi-coated filter is almost double the price. Comparing the two what are the benefits of the multi-coated filter over the regular filter?
The link you gave shows "Multicoated to minimize reflection at the filter surfaces which reduces flare and ghosting.".
The layer of coating should be very thin (thickness comparabe with light wavelength in nanometers) and have very accurate thickness (measured sometimes in the size of atoms), the technology is expensive and this makes the multi-coated optics more expensive than a simple glass.
For more information you can look at http://en.wikipedia.org/wiki/Optical_coating for instance