I thought the 3D worked well for JP ... almost as if it were shot for 3D. Took my 5yo son to see it a few months back.
I think its related to how Spielberg shot the movie. He said he originally shot it to be "immersive" -- wanting the audience to feel like they were in the movie -- so most of the movie was shot from eye level, and with things in the foreground. Also, a surprising number of shots where things were lunging directly at the camera.
All of that translated really well to 3D. Since it was supposed to be immersive in 1993 ... the 3D made complete sense in 2013.
I saw Jurassic Park in IMAX 3D today. Twenty years after I first saw it in the cinema, I must say it was like seeing it for the first time all over again. The post 3D conversion was way better than most of today's post converted rubbish and the picture and sound was incredible.
The T-Rex attack was amazing on the IMAX screen, the Rex looked huge.
The 3D Blu-Ray looks pretty fantastic. Probably the best case of 3D conversion I've seen. They should have had the same people doing the Star Wars Episode I conversion that did this. There were a lot of cases where they added 3D to elements I didn't think they'd spend the time on. Like they rendered out 3D refraction on stuff like glasses. Really great job.