Launched this morning but at least one user is reporting a 'Things don't appear to be working at the moment' error.
Also noticed there Paypal logo image is broken which may be a clue? Thinking this is some sort of cross-site thing where parameters are not being passed but I've limited information from the error message and no log to examine.
Had some payments today so its working for some people - be interested to see whether this is his OS or browser and if there anything I can do to mitigate. Or even just some log of what is going on - note it redirects to paypal.com OK.