I'm not your normal Anime fan. As a rule, I'm not into robots, giant breasted girls with huge eyes (with the possible exception of Police Girl), or magic. But I just love the everybody has stupidly long hair from pony-tailed 70 year-old Angel of Death Walter to Dracula-spelled backward ALUCARD with the coolest guns on the planet. Then there is the vampire in training Seras Victoria AKA Police Girl-the only one in the series with short hair, unless you count Jan Valentine and of course the indestructible Father Anderson. The OVA really follows the Manga pretty closely, right down to some of the very silly asides (the "love beams").
I normally prefer my Anime in Nihongo, but WOW, BOTH of the Hellsing outings are fantastic in English, as well as Japanese (except for the German pronunciation, which is right in the Japanese, and wrong in the English).
The end credit music, Gradus Vita, I think at the end of episode 1 of the OVA (it's been awhile since I've watched) is one of my all time favorites. I like masses. I ALWAYS blow out the fuses on my surround sound system, when I play it, because I crank it up WAY too loud. That usually only happens when I hit the Berlioz Requiem, so I think I REALLY love that piece.
The first Hellsing series has some REALLY cool music for the opening sequence, which I kind of miss in the OVA, but I just watch them both. The OVA has so much more depth, because it has all of the Nazi story lines. I'm really hoping they will go to the end with the OVA. I only have up to Part 4, so I'm looking to part 5. I have Manga past part 4.