Web design: freelance or outsource?


Hi there! I’m an owner of a medium-size online shop. Recently I’ve decided to change its design to attract more clients. I’m also thinking about developing a mobile app since quite a big share of my cilents buy the goods via mobile phones. Now the question is - where should I look for people to do this work for me. I heard about Upwork where freelancers post their CV and even reach you without you looking for them. There is also qubit-labs offering web design and mobile development. Both work remotely, both have more or less same prices. How should I choose what is better? What are pros and cons of hiring freelancers vs. outsourcing companies?