-- To freelancers
I love Upwork's terms of service. Some freelancers might think it's too uncomfortable while using it. But actually, it's to protect all works and payments there. Highly recommend Upwork to freelancers. You'd better start work on Upwork with your new clients outside. Upwork will be the trustable third party to you.
-- To Clients
There are so many competitors there, though I feel happy to race with them. Clients would meet well-skilled freelancers on Upwork and get great deliveries. And Upwork will be a responsible third party between us. Hope we'd meet together there.
--- FYI, I suggest you study the Upwork policy carefully before beginning your work there.