Maybe you should elaborate more, do you mean it plays m2ts files using VC-1, H264 and Mpeg2 with full HD audio without having to install any extra codecs? Or do you mean it'll play back the whole Blu-ray structure without needing anything else installed?
If not then it doesn't play back Blu-ray ripped to harddrive. Vista will play back VC-1 and mpeg2 files with wave audio without extra codecs installed