Mimic. There, now stop claiming del Toro is perfect. Actually, it was not until Pan's Labyrinth that he really started pulling ratings higher than 7 on IMDB (and that site is well know for being generous). He has been on quite a run over the last few years, and considering the kind of money poured into Pacific Rim ($180M+), it *should* be great. This premise of synchronized movement controls through a neural interface at first (and second) glance seems contrived, highly implausible, and ultimately a hindrance to immersion. If that is the only flaw, then this will probably be a 8.5/10.
One other aspect to consider - the main production company is Legendary Pictures (MoS, Hangover Pt 3, Wrath/Clash of the Titans, Sucker Punch, and it keeps going on and on). They have some hits, but for every one there are two or three stinkers that were all billed as 'blockbusters' with heavy ad campaigns dumping Millions into ad space, before the reviewers set us straight. Now, del Toro should have been more than just the director on this, so he probably kept Legendary from messing it up. But it is like seeing the logo for Lionsgate appear on a movie you were not even sure you wanted to see in the first place. It is a really good indication that if the movie sucks at the start, it will only get worse. You only have 30 minutes to leave the cinema to get a refund, so always wear a watch and if you even look at it in the first 30 minutes, then it is not going well for that movie. I have left 9/10 Lionsgate movies in the last 8 years, all within the first 15 - 20 minutes, and none were ever a mistake. I consider Legendary to be a much better funded version of Lionsgate, but they tend to spend it all on CG instead of all the other ingredients that make good movie. I have only left 3 Legendary pictures, but for some reason I tend to avoid their releases based on their premises alone (or I am just lucky).
So rush out and see it on opening weekend? It will depend on what my favorite and trusted critics say. There is no point in flipping coins when we have reliable sources.