There is a big difference in the design of the element when comparing line voltage to low voltage. Danfoss and Nexans are line voltage systems.
Heatizon is a low voltage element. Both electric systems function the same way in that they use electricity to heat however they accomplish in different ways.
Also, line voltage being what it is, has stricter reg's when it comes to placement in the ground. (Check your local reg's for just how deep they can be placed) Since it uses 240v in the element it must be deeper in the ground for safety's sake. Therefore it must, by design, create more heat to do the same job as low voltage which can be 1" from the surface.
How much square footage you cover will depend on your budget. Tracks are good until you are faced with about 5" or more snow. Then they tend to either collapse in on themselves or your vehicle will 'plow' the center uncleared path in on the tracks as you drive in. So, for light snow falls or keeping the path clear after the plow leaves it's 1/4" of ice behind, they will work fine. But remember, if we get a nor-easter, they'll be uselss until the plow leaves...each time!
An 8' wide path will remain clear and allow you in an out without a problem 80% of the time. The nor-easter will require pre-activation to get the driveway 'warmed up'. Though they are still tough to keep up with.
Remember also that snow melting systems are not designed to melt through snow, they are designed to prevent it from building. So, if you don't use an automatic sensor to activate it and you forget to activate it in time, you will have a nice igloo developed on your driveway that will take the sun and a lot of electricity to melt through.