The UK has a more mature legal system, more public support for Assange and, because of its size, is less subject to influence, particularly economic influence.

The UK has a more mature legal system, more public support for Assange and, because of its size, is less subject to influence, particularly economic influence. We also have evidence that the UK courts resist US extradition requests via the McKinnon proceedings. Finally, the US obviously wants to prosecute Assange and the publicly acknowledge existence of a grand jury investigation proves it.