As compared to the DVD's cover:
About 50 minutes in length. The Blu-ray Disc version comes with English dubbing, as well as subtitles in 5 languages: Japanese, English, French, Spanish, and Chinese. The DVD release has Japanese and English subtitles.
The Blu-ray Disc version's price is 5,040 Yen (inclusive of tax), while the DVD version is 3,990 Yen (inclusive of tax). Both scheduled to be released on March 12th, according to the source, Amazon Japan.
However, the first batch of audience to watch the OVA will be those who can get it from Sony Entertainment to be watched on PSP and PS3, which will be available on February 20th. A preview for Episode 1 is scheduled on January 20th, as reported in this previous posting.
Images are from Amazon Japan: Blu-ray Disc, DVD.