Lightscribe is a method of using a laser to etch onto the serface of a disc. The end result looks very professional BUT it is only mono - no colour, and it is very slow, approx 20 minutes for 1 disc.
Several printers will brint directly onto discs, generally Epson and Canon, however, as you have stated you must buy printable discs. Again the results are very good, in full colour, and much quicker than lightscribe.
If it were me, I would go for the printable disc option every time.
Hope this helps