Neither is better, and both have their pros and cons.
The upside of working with a distributor is knowing your film’s release will be supported and carried out by a team of professionals. The downsides, however, are that you are relinquishing control of your film and sharing revenue with another company.
Self-distribution has its own advantages and disadvantages as well. Instead of giving up control, you retain ownership of the film’s release and the revenue it generates. However, to perform well, you need time, money, and a strong understanding of navigating releases and promotions.