I am not going to say anything one way or the other about Serious Partners but I will talk about checks. European banks treat paper checks like they have the plague or something and when you have a problem with them those banks can be wholly uncooperative. Paper checks have really become almost obsolete over there and when they say it is going to take up to two weeks you can count on that as a minimum.
I know it does not help for the check that is floating around out there now but I would seriously consider bank wires or Paxum over checks especially when dealing with any company in Europe
