http://gamerscoreblog.com/team/archive/2006/03/01/533472.aspx

edit: and for clarification, the fellow that posted this blog is also a MS employ.
Price. One company out there has a $1,800 Beta-ray player (no release date) one that doesnt even play CDs! For 1,800, you could get a $500 Toshiba player, and about 40 HD movies.
Industry support: Looks like the pendulum is swinging back in HD-DVDs favor. As an analyst quoted in the article says: It's only a matter of time before people start backing out of the Blu-ray camp." If thats the case, it might be because of. . .
Beta-rays own difficulties: Microsoft had serious doubts around the technical feasibility and pricing of Beta-ray for some time and our fears now seem well founded. Sony is hinting PS3 will be delayed because of Beta-ray, and thats with Sony driving the Beta-ray standards. If even Sony cant get it to work right, it raises lots of questions. A little reported fact (and one that the New York Times was confused about) is that the first Beta-ray discs will actually hold less: only 25GB compared to HD DVDs 30GB. That means less room for high definition extras and interactive features, which HD DVD says they fully intend to support.

edit: and for clarification, the fellow that posted this blog is also a MS employ.