I have this one magazine,
Wizard Anime Insider (highly recommend it :thumbsup

and there's this one article in there that discusses about the Hellsing Ultimate OAV and 10 things to know about the new OAV. I'll just touch up on a lil' bit about the 10 points they have:
10.
It Gets the Story Straight
The storyline in the OAV covers what the manga is all about; the Hellsing Organization going up against the Millennium Group, which is consisted of supernatural Nazis who invade England hoping to spark a never-ending war. The producers say the goal is for each DVD volume to cover exactly one manga volume for the sense of near-complete accuracy.
9.
It's Got New Old Characters
Some characters that weren't in the first series of Hellsing are in this one; such as Pip Vernedead, the Millennium Group members such as the were-cat Schrodinger who can alter reality, the tattooed mystic Zoran Blitz, and the sharpshooter Rip Van Winkle.
8.
The Blood Will Flow
"The original TV series was restricted in the depiction of violence because it was meant for TV broadcast," Satoshi Fujii, senior producer of the US branch of Geneon Entertainment said. "But because this is an OVA series, there's virtually no restriction.
For example and I'll use spoiler mode:
| spoiler (highlight to read): |
| In the first episode of Ultimate, Seras Victoria rips apart a host on gun packin' ghouls with her hands and then grinning all the way, stomps on the lone survivor's head into a bloody gore of paste. Also, Alexander Anderson is more gruesome (yes, apparently that is possible) for example when he and Alucard fight, Paladin nails the vampire to the wall with his blades, hacks off his head, stalks a terrified Seras, and then dices up Integra's bodyguards as well. |
7.
It's a Prequel Too
Also included with Hellsing Ultimate are scenes from the manga prequel, Hellsing: The Dawn, which is about a younger Walter and Alucard fighting the Millenium Group during the ending time of World War II.
6.
Seeing is Believing
With a more increased budget on time and money itself, the animation is much more detailed and action in Ultimate. Also, the animators are adding in making the OAV more accurate as some shots from the OAV are incredibly identical to the panels of the manga.
5.
It's Got Familar Voices
In Japan, Hellsing Ultimate was able to get the original cast of the first Hellsing anime (with the expection of Alexander Anderson) for Ultimate and Geneon is looking to do the same as well. For the English dub, Geneon Entertainment is trying to get the same cast as the first one as well such as Crispin Freeman as Alucard, K.T. Gray as Seras Victoria, and Victoria Harwood as Sir Integra Hellsing.
4.
It's Broken the Sound Barrier
For the original score of Ultimate, there's quite a number of contributors such as Hayato Matsuo, who also did Final Fantasy XII and Magic Knight Rayearth. There's also the Warsaw Philharmonic Orchestra who in the past did Escaflowne (with ol' boy Yoko Kanno), Wolf's Rain, and Fafner. The audio uses a 5.1 mix with the full orchestra, giving the anime a very real theatrical feeling.
3.
It's Got the Right Writers
For screenplay, the producers brought in Hideyuki Kurata, who penned Read or Die and also Yosuke Kuroda who did Trigun. The two of them, when before grouped together did Excel Saga, brought in an Anne Rice feel to the script as well as the black humor that the manga displays perfectly.
2.
There Will Be Extra Credit
Both Japanese and English versions of the Ultimate OVA comes complete with an elaborate sculpted relief of Alucard. It's like a picture frame so it can be set on your desk or hung from the wall.
1.
It'll Satify Your 'FMA' Craving
The tagline for Hellsing Ultimate is "The bird of Hermes is my name/Eating my wings to make me tame". Not only is that inscribed on Alucard's coffin but its also originally from the Ripley Scroll from the 15th century that in a very symbolic description in a poem, describes how to create the Philosopher's Stone. Also, Kouto Hirano (the manga's creator) is a big fan of FullMetal Alchemist. Even so as to have the Millenium Group do a bonus cosplay parody of the FMA series in seventh volume of the manga (I've read up to the seventh volume and that was quite funny.)
So there's some ten points to know about the Hellsing Ultimate OVA, and I've read the manga and since it's based off that, it should be damn good. Hope you enjoy this.
Peace.