Beside some of the common bugs, It's seen as a departure of quality for Apple. They abandoned a mapping solution that is better (Google Maps) and replaced it with something that was deemed sub par by a huge contingent of the tech community. People "rag" on it because its not a quality product that Apple is known for and it was an embarrassment for the company. People still harp on it to rub salt in the wound. Personally, Apple maps isn't terrible, it's just Google Maps has been refined for years longer and has a massive user base for use it more than the Apple variation. It's not as refined as G-Maps and in time could be refined to the same degree if not more so.