As the provincial capital, Taiyuan has a large population and relatively developed infrastructure such as food, clothing, housing and transportation. In addition, the public security in Taiyuan is also better. However, although the GDP of Taiyuan is higher than that of Weihai, there is still a certain gap between Taiyuan and Weihai in terms of environmental quality.
Weihai has a beautiful environment, but the transportation is not particularly convenient and the population is relatively small, which leads to the relatively slow development of IT industry, clothing industry and food industry. In addition, per capita income and consumption in Weihai are relatively high (mainly due to high prices).
To sum up, Taiyuan and Weihai have their own characteristics. Taiyuan has advantages in GDP and population, and Weihai has a good performance in environmental quality and per capita income. You can evaluate which city is more developed according to your own needs and preferences.