Fiverr Freelancer and Upwork
I assume you can guess it by its name i personally experienced that freelancer.com is the only one freelancing plat form where you can see continue project posting.
In the freelancing online world fiverr is one of the reliable platform where you may find highly professional and talented professionals
Upwork is a internationally well known freelancing website where 1000s of freelancer go online for companies or employers who are seeking technical experts online
In the conclusion of all 3 freelancing websites i believe fiverr is the only one which is user friendly, easy to understand and easy to work on, Upwork is one of the arrogant and complicated site, arrogant refer to their terms and use of provding platform they behave like they did not created this website for their business they have done this to serve the world for free and people are so blessed because of them which is not true i have seen so many bad comments of other people too.
Freelancer.com is 50/50 its easy to use but to many things to manage such as authentication activation and all, the way it runs like comments on YouTube on a live TV hot news which makes you feel that its managed bad or they need to improve their bidding feature and change it to a different way