It depends on your objectives and the intended usage of the language. In mainland China, people speak simplified Chinese, while those in Hong Kong, Taiwan, and other Chinese communities overseas speak traditional Chinese. Learning simplified Chinese may be more practical if you plan to visit or do business in mainland China, whereas learning traditional Chinese may be more relevant if you plan to visit or work in Hong Kong, Taiwan, and other overseas Chinese communities, or if you are interested in Chinese culture and history. In the end, it's your choice, and it should be based on your own needs and preferences. No matter which writing system you learn, you will be able to talk to people who speak Mandarin in mainland China or Taiwan.