We were replacing the existing stove-top (about 15 years old) on a granite top and we had to be careful of the "cutout" size due to the existing cutout size (we didn't want to replace or alter the existing granite.  It took a while to find but this model fit perfectly.  Easy to use - only problem (typical for glass tops) is always having to clean it + the surface is very sensitive and sometimes when you clean it, it thinks you're trying to start the cook and you get a little beep.  Not a big deal