I had a number of problems which I reported in another post - http://forums.dlink.com/index.php?topic=3533.15 - but I'll repeat them here.
The 323 would work fine initially after startup but after a while I would get part way through copying files from my PC to the DNS-323 and I would get a "network path no longer available" message. After this I would not be able to access any files on it. If I turned it off and started it up again it would be okay again. I also got pink drive lights and intermittent reporting under status that my drives needed rebuilding. Again, turn it off and back on again and all would be fine again, for a short while. I gave up trying to track the problem down and reinstalled 1.05, since when it has operated flawlessly.
One thing I am wondering though is if the UK ftp site has the wrong build of the firmware on it as it appears to say it is a 'beta' version - the filename is this.. NAS202C_DLINKEu_DNS323.1.06b65(1.55.1203.2008)(BETA)