In the heirarchy of cooktops, induction is king. Although induction is powered by electricity, it should not be confused with traditional electric cooking.
Induction provides instantaneous results. The speed of heating a pan is amazing (surpasses gas and electric in speed and control), it does not throw heat (other than the hot pan), and the lack of heat generated beneath the surface means the cooktop is much cooler than either electric or gas, because there are no heating elements in the unit. Also, induction costs far less to operate than gas or electric.
This unit has digital controls (with a lit display that only shows when it is on), and I know, for example, that olive oil will burn in the pan above 5, but 4.5 is perfect for sauteing. And it will remain perfect for sauteing throughout the entire cooking process, it will not get hotter or colder.
Furthermore, you can store anything on the cooktop (we keep a bottle of olive oil on there, as well as a non-magnetic spoon rest. They stay cool to the touch regardless of how many units are on.
Now there are downsides.
1. Cost: cost prohibitive for many, by far the most significant factor. There are no freestanding range/oven combos, which means that you need to spend money on individual range and oven to get a functional kitchen. Furthermore, unless you have a 40A cooktop in place, you will need to upgrade your electric. The total cost for us was around thirty two hundred for both the wall oven and the cooktop, with an additional cost of $150 for the electrician, and about $300 in replacing the pans.
2. Cookware: although most high end pans are made to be induction compatible, the majority of widely available cookware is not. Especially non-stick. I found a couple nice "eco" non-stick pans at a homegoods store, but be advised to take a magnet along with you shopping, and only buy pans to which it sticks. That being said, all-clad is typically induction compatible, and there is a wide movement to making pans that way.
3. Probably not a wise investment at this point if looking for a return on a home renovation for sale. While many people discover the benefits of induction for themselves, it hasn't taken off in the US yet, and most people won't know the difference until using it. I doubt people would recognize the benefits if we went to sell the house. Perhaps a brochure would be in order...
Now for those that hate electric cooking, but don't have gas lines, this is an amazing solution--I think it is far better than the other methods of cooking. Also, if you frequently cook but have a smaller kitchen, this will keep it cooler.
If you have gas lines, I'd have to say that the benefits of induction (compared to gas) do not outweigh the initial cost. This cost could be recouped by energy savings if you cook A LOT, or by weighing in other considerations, such as small children being burned.
The 30" is very useful, and is equivalent to a standard freestanding cooking range. The 36" model would be appropriate if you are accustomed to having a 6 burner cooktop.
I don't have any basis for comparison to other induction units, but I cannot find any faults with this unit.
UPDATE:
After cooking on this for over a year, I have a few additional comments:
1. Some induction compatible pans make noise when heating, not loud, but rather annoying.
2. The glass has scratched slightly in places. Still looks very sleek though.
3. Controls are annoying to clean. Despite the "control lock" button, when you clean the rest the water activates the buttons, making an error message and a beeping noise.
4. There should be a better way to seal off the edges next to the countertop. Has anyone tried silicon?
5. There are now "all in one" cooktop/oven slide in units available.
UPDATE:
Barkeepers friend works extremely well to clean the cooktop