This is a review of the Blu-Ray edition of the film, not the film itself.
Compared to the DVD edition (which I also own), this is a huge improvement. The resolution is higher; this gets the extra details and not just blur. The color balance is better: the DVD is rather blue, but the Blu-Ray gets it just right. The only thing wrong with the picture is the occasional speck of dust from the film transfer. I can't comment on the sound, since I only listen through headphones.
The disc itself comes packaged in an unusual slimline case, with a catch that must be pulled outwards from the case before opening. I like the case; in fact, I wish all my cases were like that to save on shelf space.
If you're considering buying the Blu-Ray and are worried about the poor-quality transfers that plagued the DVD releases, don't be. The quality is everything that can be expected from a Blu-Ray release of a 1980 film. Enjoy this cult sci-fi classic again in glorious HD!