blue-ray? i'd rather take a death-ray gizmo thank you very much. but anyway if you really want to find out the nitty gritty of blu-ray go to
http://en.wikipedia.org/wiki/Blu-ray_Disc.
i have burnt one cd and one dvd in the last year and i only had about ten faulty burns since i bought my first writer. so yes optical storage mediums are reliable. but the thing is that you have to take care of your discs. put them in a case, dont leave them in a cd/dvd drive for extended periods, no excessive heat or cold. and dont touch the recorded surface.
i always tell people when it comes to pc parts and accessories, you get what you pay for. so dont buy cheap blank discs or components. it sounds silly to do it but one of the best pieces of advice i can give anybody is that before you buy something computer related, google it and read more than one review of whichever product you are going to buy. it may save you from buying a lemon.