English version is still in the alpha version and has some trouble now, however, Japanese version is far more solid. I really use it for seven years and have built my database with ~24000 items and with ~4.2 GB.
As it employs Windows echo-file system, all the items remained as it is (with directory/file structure) even if I met to have trouble with this soft.
This point is similar to EagleFiler and is the most important reason why I have selected EagleFiler in Mac world. My recent task is data transfer from KamiCopi (Windows XP [Guest]) to EagleFiler (OSX [Host]) via Shared folder.
KamiCopi is shareware with ~$25 and KamiCopi Lite is freeware forever.