Macbob:
I'll be really concerned if I have another problem, but their response time was so fast that if I never have another issue, I'll just be impressed by how good their customer service is.
Note that I've talked to a few sellers, and they hadn't heard of any issues with the LCDs since last year when they fixed the early problems with the LCD-3s. Of course, it is likely that most people with issues dealt directly with Audeze, like I did, so the sellers had no idea there was any problem.
Note also that they are a small company, and if they were getting a high percentage of LCD-3s back, it is unlikely they would be able to fix and return them in a day.
Finally, Audeze has sold a LOT of headphones to head-fiers, and if there was a large problem, it would be all over these boards -- like their early LCD-3 problems were. I haven't seen reports of widespread failures recently, so likely we just got unlucky, since a certain percentage of all manufactured products have defects, and even a 99% reliability record means that 1 of 100 of us gets one that breaks.
Hope that makes you feel a bit better...