Mum had one of the earliest ceramic hob tops. She had to buy special absolutely FLAT bottomed glass/ceramic cook pots to use on it. The burner areas never yellowed at all.

I understand the newer ones don't need the special pots and DO turn yellow. It has to be cleaned with a special cleaner...something similar to 'Soft Scrub' or it will scratch.

Mom loved hers. I'd never have one because I can't use my cast iron on it. I also 'inherited' all mom's cast iron when she bought her stove!