I really don't understand what is the difference between them. I would also like an opnion on which is better and why. :confused:

BLU RAY holds more data and a lot more movie studios are backing blu ray now... so go with BLU RAY

Technically Blu Ray is the better idea and has more backing from the content providers, but is more expensive.

The audio and video quality are similar between the two, as they both use similar encoding methods.

This wikipedia article compares the differences between the technologies quite comprehensively:

Comparison of high definition optical disc formats - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Comparison_of_high_definition_optical_disc_formats )

Thanks for the help I'm think I going to go with blue-ray.
Thanks capuchin for the wikipedia site, really helps