Only recently did I get around to watching the final two movies of the Harry Potter storyline, and they certainly are very different beasts. If you haven't watched any of the previous movies you are going to be quite lost too, so I wouldn't start here and go backwards.
After the opening Part I is a snooze fest, due to the heavy reliance of "intrigue" in the plot and prior connection to characters introduced in earlier films. If like me, you don't remember or don't care about said characters then this is certainly not going to keep your attention. From an anime watcher stand point I'm almost inclined to say it's filler.
What the hell are we watching?
Nothing wrong with the acting or the effects, it's just really the plodding storyline that kills it. No such issue in Part II though, since they can finally focus on all the action as the forces or good and evil battle it out, already making it a much more entertaining film for me.
There's a fair bit of death happening in both movies too, but for me it's almost like the movie maker tried to keep in more to the PG side of things with many characters dying off screen - Harry just sees their bodies or hears about their demise later on. I suppose that's how it is in the books(?) but I for one would have liked to see just exactly how they died, because gore = fun.
I think the main problem though with both movies is that it's counting on you to be invested and on-side with people already, which is fine if you are. Less fine if you aren't. That's not a problem with these book-end movies per se, but it certainly means its a problem in the earlier ones.
All up, I give Deathly Hallows I 1.5 brooms out of 5 and Deathly Hallows II 3 wands out of 5. For non Potter fans who haven't yet seen them, Part II is entertaining enough but you might need to wade through Part I to get there. It really is a "play it in the background while doing something else" film.