I don't think this has anything to do with the treaty texts.
UK judges are known to stand up to the political establishment when parliament doesn't get their ducks in a row and very, very carefully make sure they are consistent with UK constitutional law, which does in fact provide fairly strong protections, and even more so coupled with the Human Rights Act. This to the ongoing exasperation of UK politicians. Swedish judges does not have a similar reputation.
I could very well see a UK judge deciding that extradition would not be compatible with rights guaranteed to him under UK or EU law, regardless of the treaty, due to the state of the US legal system, but I really can't imagine a Swedish judge thinking twice about it...
Maybe I'm being overly cynical, but personally I would not take my chances if Sweden if I didn't really have to if I was in his shoes.
That isn't how extradition works. This is an extradition hearing on a EU arrest warrant, the UK (as the arresting country) would not be able to extradite to anywhere BUT Sweden, despite any agreements with the US.
The other factors you must take into consideration is that in the UK, the judicial system is separated from the political one (not so in Sweden) and you would have to deal with English CommonLaw. Compare this with Sweden where the prime minister has already asserted Assange's guilt in parliament for an on-going case (in the CommonWealth countries or the US, this would be grounds for a mistrial).
Although it is tempting to think that because the UK must certainly be one of the US' closest ally that it would bow to the US pressure, there is a lot of legal red tape to go through but in the last 7 years the US has had significant influence over Sweden in legal terms. For instance Sweden once had a strong stance on matters of privacy but now all call records and IP records are stored in the Titan Traffic Database and warrant-less wiretaps are now possible through the FRA law but because of the vast amounts of data with both systems, the data is handed over to the US directly for signal processing (which may be a violation of EU privacy laws and UN Universal Declaration of Human Rights).
UK judges are known to stand up to the political establishment when parliament doesn't get their ducks in a row and very, very carefully make sure they are consistent with UK constitutional law, which does in fact provide fairly strong protections, and even more so coupled with the Human Rights Act. This to the ongoing exasperation of UK politicians. Swedish judges does not have a similar reputation.
I could very well see a UK judge deciding that extradition would not be compatible with rights guaranteed to him under UK or EU law, regardless of the treaty, due to the state of the US legal system, but I really can't imagine a Swedish judge thinking twice about it...
Maybe I'm being overly cynical, but personally I would not take my chances if Sweden if I didn't really have to if I was in his shoes.