Want to keep fit and learn Sanda or Tai Ji Chuan?

If your main purpose is to keep fit instead of fighting with others, I recommend Tai Ji Chuan. The reasons are as follows: Because Sanda is intense, young people certainly have no problem, but with the growth of age, people can't always stay at the peak. If you practice Sanda forcibly, you may hurt your health. Tai Ji Chuan's exercise intensity is not as strong as Sanda's, so he can practice all the time when he is old. However, if Tai Ji Chuan is not used in actual combat, it can promote blood circulation and slow down the speed of physical function degradation (in fact, moderate exercise will have such an effect).

If you want to play fast, I recommend Sanda, because Sanda is dominated by storm, and its technical accuracy is not as high as that of Tai Ji Chuan. In fact, it is very difficult to practice Tai Ji Chuan in actual combat, because this kind of slow and fast kung fu is very difficult to do in actual combat. Many of them are feasible in theory, but very difficult to do. Many of them, such as Aikido technology in South Korea, are in the theoretical stage, and some of them are skills that no one can do in reality (so far). Moreover, the basic skills required for actual combat Tai Chi are very deep, and it is even more difficult to reach the peak in actual combat without small achievements in one or two decades.

The above is just my personal opinion, please don't take it amiss if there are differences. I hope I can help you!