About a month ago I purchased some ADK TL-MPs from Cascade Media and some Studio Projects C4s from and "Authorized Dealer" off of Ebay. With my wonderful luck one of the ADKs had a rumble and one of the card caps on the SP C4s had a rumble. Trust me, I tested the hell out of these to make sure that I wasn't crazy.
I called up ADK and talked with Steve on the phone. Super nice guy who didn't sound rushed or irritated that I was having a problem. He shipped out another full set of mics that day, even without getting the old ones back first. Amazing service.
Then I called up Studio Projects and talked with someone on the phone about my card cap rumble. They sent out a new set of caps that same day. The rumble kinda sounded like wind noise yet the mic was in a closed room.
They actually told me a slightly scarry trick to fix the rumble problem that sometimes happens. Supposedly the rumble happens when moisture gets inside the microphone on the diaphragm. To fix the problem he told me to put the bad cap in the toaster oven at 150-200 degrees for 3 minutes. He also recommend adding some lemon pepper sauce but I think he was joking. Since he was already sending me out some new caps I figured I'd give it a try. Popped it in the oven for 3 minutes and then let it cool. Put it back on the body and plugged it in. The rumble was still there. I let it sit for a day and baked it again. BAM!! Fixed. I don't hear the rumble any more.
So in conclusion, two very crappy situtions that could have been very annoying both turned into great experiences. I would highly recommend buying mics from both of these companies not only for the quality of their mics but also the quality of their customer service.
Adam