It took me an hour and a half to get the passcode email. I tried the link, the servers were down - so I emailed Slate Support, and they got back to me in an hour (despite me emailing them at about 2am US time).
I tried again the next day, got the login page but couldn't login (as I posted on here). Left it about half a day and still no luck, so I emailed Slate Support again - and again they replied within a couple of hours. The next day I got the "Server upgrade" message just as they'd told me.
Tried again last night, got in first time, downloaded the whole thing in around an hour; no problems, no slow speeds, no corrupted files.
So yeah, it has been really messy and it's taken longer than it probably should have - but the Support guys at Slate have been quick to reply to me both time I emailed them, they've been courteous and apologetic, they've been up front and said "yes we're having issues, but this is how we're trying to fix them, please be patient" rather than just fobbing me off with excuses, and they've written the emails personally rather than just mailing out a stock response. Like Executioner said, if I'd ordered a hardcopy of it I'd still be waiting for delivery - and if there'd been a problem with that, it would have taken a lot longer to sort out.
Of course you're going to get annoyed if you sit there refreshing the page every 5 seconds going and it still doesn't work. If it doesn't work, go do something else for a few hours (at least) before you come back to it. Seriously, if you feel "outraged and humiliated" because the 'ickle bitty dwum samples won't download, you have more pressing issues in your life than a borked server.
Steve