i'm always wary of hype trains myself, anon, but hellsing ultimate is really very good. its only honest failings are in its soundtrack compared to the original and that the initial episodes are a little slower/don't tie into the overall plot as much. if you love vampires, gratuitous amounts of gore, and gorgeous animation, you'll like it.

that being said, keep in mind you have the anime (just hellsing) and the ovas (hellsing ultimate). the anime departs from the manga it's based on, hellsing ultimate is the more accurate adaptation. it also gets major points for having a female protagonist who manages to kick ass while not falling into the same bland tropes most ~badass ladies~ tend to.