I'm going to lend another vote for this. I didn't pay the extra $100 "rush fee", and I waited in frustration as I read comments from others who ordered after me and got their JH-13s before me and reported perfect fits. When I got mine, they were quite bad: ridiculously bad fit and tons of bubbles throughout the acrylic. They looked like whoever made them didn't care at all. I sent them back with a set of newly made impressions — both to demonstrate how off they were and to ensure that they had a set of good impressions — and have been waiting two weeks since they received the new impressions and the returned IEMs. I'm still waiting to hear back.
Based on the feedback from others who have paid the rush fee, I now believe that the "rush fee" should be considered as part of the price of the product by any customer who wants to be taken seriously and treated as a 1st-class citizen. If I had paid the rush fee, I get the feeling that my order would have been treated as an "important" order for a preferred customer. I think that is the main benefit: the "rush" is just an extra perk. Certainly, my experience does not make me feel like an important customer — more like a 2nd-class citizen to the celebrity musicians that they serve and those who paid for preferential treatment. (and still no product or even any indication that there will ever be... although I trust that this will eventually be worked out.)
Although I can't be entirely sure that I wouldn't have faced the same problems if I had paid the extra $100, I have definitely paid far more than that in trying to overcome JHAs inadequacies: in the price for the new impressions, return shipping, and time required to leave work to get the impressions, ship them, and attempts at contacting JH Audio.
So, yeah... just pay the extra $100 and consider it part of the cost. Then you'll have some leverage if you end up in a situation like me.