blu-ray burner info

[Dunc]

I helped a neighbor resolve a minor glitch.

Anyway, I noticed that his system had a blu-ray double layer burner (+/- 50 GB data) installed.
While media costs/GB are high (vs imo an external hdd) hoping someone could give some idea of reliability of these units. Do they burn successfully all the time? Is the data able to be recovered reliably? How well is the switch from one layer to another effected? Good media brands? Any ratings of hardware?

While I think it is an expensive way to go, he already has the hardware ( used, I think for video, not data). Re-writable media would be one way to go. His data storage needs would fit in the capacity of this media.

Thought/opinions/suggestions appreciated