We've had our Frigidaire cooktop for 18 months. It performed well, but the two large burners being next to each other caused interference issues with bigger pans. It's not easy to clean around the knobs and I wish there was a away to accommodate better cleaning without having to remove them.
Last week after turning off the left rear burner and removing the pan, we no sooner turned around and walked away when we heard a noise like a rock hitting a car windshield. When we looked at the cooktop, there was a spider web of cracks starting at the left rear burner and emanating out. 
We are an older couple that has never dropped anything on this cooktop and are very careful about using only glass cooktop cleaning products. My warranty company tells me they don't cover the glass and I need to contact Frigidaire. So here I am, after only 18 months I'm forced to purchase another expensive cooktop. 
I'm unimpressed with this cooktop and will consider other manufacturers moving forward.