Story: feels familiar; no surprises; you've seen it before in other movies. Cliche, as are the one-dimensional characters. Cinematography: beautiful, sweeping, epic, every shot real or CGI or both: seamless, alluring, major visual storytelling here. Acting: meh. Believable, as far as you need a comic brought to life to be. FX: a major step up, but not perfection. Cameron wisely avoided too many scenes mixing humans w/ aliens/avatars and wisely shot live action to look as much like super-CGI as possible - but the shots with blended technique give the lie to the illusion. And what gives, Cameron? Doesn't anybody SWEAT anymore?
While the movie has its problems - there are minor inconsistencies in the internal logic and it takes a while to get past the exposition and to the start of the tale - it is an excellent piece of work overall. I have a feeling that it will be referred to by film buffs and historians long after the general public has forgotten about it. It is a tale that transcends its own genre. It has the superficial plot elements of The Fly, but shares a geneology with 1984, ET, Predator, and The Tempest. Sharito Copley does an incredible job and should be nominated for an Academy Award.
Gorgeous cinematography barely makes up for a lack of special effects, with the exception of Dumbledore's firestorm. The music is also rather flat - appropriate, but lacking the majesty and scope of John William's original scores.
Acting takes a huge step forward. Radcliff, Watson, and Grint's maturity is evident and each breathes a new air of believability into their characters, unlike the rest of the teen cast. The adults always bring full-fledged characters to the screen, even when they don't say a word.
Characterization is nothing without plot, tho. This movie is the weakest, lacking a cohesive storyline of its own & inadequately serving as a bridge to the final episode.