I've been meaning to mention this for a while now but haven't got around to it until now. I'm a big fan of Adafruit, they have a lot of great hacker friendly products and provide a huge amount of information about using them. Unfortunately, being outside the US can push the cost up due to shipping charges so I don't order as much from them as I would like to (I tend to keep adding things to my wish list and do a fairly large order once every six months or so).
I've never had any problems with them before but my last order arrived with a missing component (One of the Pi T-Cobbler was missing the PCB). Luckily they have a form which lets you easily report problems with an order so I filled that out, sent it off and expected not to hear anything for a few days.
The next morning I had a reply - a nice apology and a tracking number for the package they sent containing the part I was missing. I was very surprised and pleased at this - I had expected a store credit at best, the cost of shipping the one missing part probably consumed all the profit they made on my order.
This is the measure of customer service, not that things always go right (they never do, especially at the volume of orders Adafruit probably deals with) but what the response is when they don't. I have to give Adafruit a big thumbs up for their response - they certainly do their best to keep their customers happy. If you are looking for cool hackable parts definitely go and look at their site - highly recommended.