We bought this cooktop about a year ago and writing this review in 2015. We read most of the reviews before we purchased the cooktop and was a bit skeptical, especially about the concerns over the "plastic knobs and stems", the grate height and taking a long time to boil water and subsequent escape of heat, and finally paint/writing coming off when cleaned.
First, we absolutely love this cooktop. For a 30 inch cooktop it has a lot of surface for pots/pans. Keep in mind that it is a 30 inch surface that GE has maximized; not all pots/pans will fit at once.
The lock/unlock feature is one of the reasons we bought it as we have little children who can be curous. When locked, their is a light that illuminates and if someone tries to turn on a burner there is a buzzer sound that activates and can easily heard throughout the house.
The up front controls is another reason we purchased this cooktop as most offer them in the middle or on the right or left side. The control placement on this cooktop let you control the heat with having to reach a across or near the heated grates.
We have not encourted any issues with knobs or stem and we have had this cooktop for about a year. The knobs snuggly fit the stem but with constant pressure straight up we are able to remove them for cleaning.
The cooktop is easily cleaned and cleans up well! I was very careful to read the entire owner's manual to ensure I maintained this cooktop properly. I did not want to scratch or ruin the surface by using an abrasive cleaner or an improper pad/rag/brush. We typically do not have any problems with cleaning the cooktop with using just a damp cloth. For tougher messes we use a damp cloth with dish soap.
The only issue we have with cooktop is does take a bit longer to boil water when using a burner other than the center burner. The center burner will boil water quickly! The solution to boil water on another burner is to first get the water boiling using the center burner and when the water starts to form bubbles, turn on an outside burner and put the pot over it.
The one thing we will do is remove the cabinet that over the cooktop. With the cooktop having commercial style grates, the cabinet over the cooktop looks like it is trying to suffocate it! It will look much nicer once the cabinet is removed and a hood is installed.
I Cannot get enough heat from burners--takes forever to get to boiling point. the grates on top are to far from burner and it loses the heat before reaching the pot. Very disappointing. GE should have an alternative grate where the height of the burner and grate is not too far and it would not lose the heat.
I decided on this cooktop to put in my brand new kitchen because it had the griddle accessory and the burner controllers were on top of the cooktop further away from little fingers. There is also a 'lock' on the controllers and an alarm goes off if they get turned on with the lock on. I use a waterbath canner for canning fresh garden produce and the middle burner with is going to be amazing for that! I am so happy with my cooktop and how easy it is to clean. Its a nice heavy duty appliance in my kitchen that I am sure will be one of the most used appliances for years to come!