A few years ago, I made the mistake of buying a Mac Pro from them - a G5 2.7 DP - for similar money - worked great for a few weeks, then started playing up. Contacted them, and their reply was that if it is still working then it was OK. Came with only a very limited warranty (can't remember if 1 month or 3) but shortly after expiry of same, it stopped altogether. They refused to deal with me at that stage. I took it into a Service Center, was told the motherboard had gone - around $1K to replace, told them to go ahead - then they came back to me and said that the CPU's had also gone, would be another $1200 or more. I worked out fairly quickly that this was not sounding like a $3500 machine so canned the process. In fairness to MOAT though, I do have to say that they offered a 1 year warranty for extra $$, which could have changed the outcome.
Bottom line - look on ebay, get an idea what the going price is, and if it is reasonably close approximation, then consider the purchase, but only with as long a warranty as you can get.