There are no absolute rules. It's all related to media you have available.
Flashing your burner with a certain sequence of firmwares don't have any effect on burning quality.
You can find that a certain firmware give you best results, and this is due to the too big variability in dvd media. But this is all. Some users (mee too) find that the best firmware available until now is BSLB, but only because with the media available to me I obtain the best results with this firmware.
Media variability is so high that different users using the same burner model that do a burn with discs from the same box usually obtain different results.
Too bad there are not absolute rules. The only way to find what firmware give you best results is to do some burnings and scanning discs.
It's possible also that you obtain best results for a specific media with a specific firmware so you can decide to use a specific firmware for some media, and a different firmware with other media.
:doh: Zebadee preceeded me