They all use different 3D technologies and different glasses.
I can't say I have done a conscious A/B comparison but in Wellington for example the Embassy uses Real3D, Reading Dolby 3D and Event Real3D. The only movie I have seen in Real3D at the Embassy was the The Hobbit which was spectacular but that was 48fps also,.
I got interested only because I wear glasses and I found places selling 3D clipons that make it easier for the viewer with glasses to experience the 3D picture. But then I discovered that the different technologies require different glasses and nobody is selling after-market Dolby 3D glasses, only the Real3D ones.
Real3D glasses are designed to be disposable which is why I guess the Embassy charges $1 for them and you can keep them while Reading asks you to return theirs for cleaning and reuse.