For those still skeptical about the post-converted 3D, the following are del Toro's recent quotes regarding the 3D version. And judging by some of the other 3D screening responses I have read, it seems the 3D is really done well.
"For action, adventure and genre cinema, I'm now a converted fan of 3D. I asked the studio (Legendary Pictures) for the complete control of the 3D. I asked them for 40 weeks or so to get the 3D conversion, it usually takes just 8 to 12 weeks, and they agreed. As I'm a complete control freak, we achieved a 3D conversion that I think people will be very happy with it. It's now my favorite format for the vision of this movie, but I don't think 3D is for every film. If you can watch Pacific Rim in 3D, make sure to watch it that way."
And his quotes from last year.
“What happened was, in the weeks and months following Comic-Con, what I asked from the studio was to agree to four points that I wanted to do. The more the ILM shots arrived, the more I realized that there were only a few shots that would miniaturize. I asked the studio, number one, that we would not hyper-stereo-lize the thing. That we would not force 3D on the beauty shots. That we would keep the giant dimensions. They agreed.”
“Number two, they agreed to something very unusual. Normally a conversion takes a few weeks. I asked to start it immediately so we could take the full 40 weeks to do the conversion. As an example, Titanic took about 50 weeks to convert. The final thing that I asked that they agreed to, which was amazing, was that I asked them to give me an extra budget, which is considerable, to actually have ILM composite the shots that are CG native 3D. We’re not giving elements. ILM is giving the composite in 3D from the get-go. That’s a huge, huge element. Now I’m going to be involved in supervising it. What can I tell you? I changed my mind."