Mikhailtech have posted a review of a stick of TwinMOS 512mb DDR400 memory. We've got a stick currently being tested, from what I've heard - this RAM is fairly fast and reliable.
PC3200 modules have got to have a very good PCB in order to achieve such high speeds, 200MHz DDR, so the TwinMOS PC3200 RAM makes no exception. The PCB is designed with 6 layers instead of the usual 4 layers that other manufacturers use for their lower clocked models. The extra 2 PCB layers ensure the signal traces are cleaner and the memory will perform as it should. The DIMM I got did not come in a retail box, but in an antistatic bag.More information at Mikhailtech