Seems to be working for me now. I am using Ice Dragon browser (varient of firefox). I had tried the inner sea primer and character folio a few days ago and had the personalising click in 10 sec message. Clicked on them today and they went to the download screen. I have to wait there. If I click the "click here if it doesn't start in 5 secs" link that'll fail (timeout) but after 20-30 seconds up pops the download.
I have then click the GM screen, that straight to the download screen, waited 20-30 secs and it download and then I did the strategy guide,up pops the personalising message,gave it a few minutes and clicked again, went to download screen and waited the 20-secs or so and download started.
So obviously still a bit slower than normal and I haven't tried any of the big core books yet but it seems to be playing ball