Baidu: As the largest search engine in China by market share, Baidu has the broadest user base and the largest number of search requests, especially in Chinese. If you are marketing to the Chinese market and your business involves Chinese search, Baidu is a great choice.
Sogou: Sogou is a major competitor in China's search market, with a smaller market share than Baidu but a broad user base. The advantage of Sogou is that it has more accurate vertical search, such as healthcare, tourism, etc. If your business is related to these industries, you can consider promoting on Sogou.
360 search: 360 search is a relatively new search engine in China, but it does a better job in security and privacy protection. If your marketing goal is to improve users' security and privacy experience, 360 search may be a good choice.
Of course, there are other factors to consider, such as budget, audience positioning, competitors, and so on. Before choosing a search engine for marketing promotion, it is best to do sufficient market research and strategic planning to determine the most suitable choice for yourself.