There's no advantage to joining a new league. There is no expansion draft, you'll still inherit lousy contracts, and you won't have any idea of how good your team is until you pay your money and select a random slot in a specific division.
With existing leagues, you can ask questions, do some research and select the type of team you want to manage (e.g., win now vs. rebuilding project), and you'll have an idea of who you'll be playing against.