I have the 1655. It was an OEM factory replacement from my 1625, which the LS feature went bad after 3 labels. My 1655 has been very reliable and I have blogged about all my burnings (see link below).
The firmware it came with is BCDB, and it works fine.
As a general rule, I don't recommend flashing/ updating to newer versions unless something doesn't work (why fix it, if it ain't broke?) Alot of times newer versions have more bugs than older ones.
I have a blogsite about the BenQ 1655 below, and update my results. I just burned my first 8.5 DL DVD with it, and it plays on some of my stand alone DVD players. The booktype setting was on DVD-ROM, and the DL DVD blank was +R. Interesting, it didn't play on my portable Mintek DVD player. I have a Lennox Sound DVD player, which skipped when playing it (I think as it got to the second layer). And I have a NextBase 9000, which played it flawlessly. I don't know if I changed the BookType back to +R, if my stand-alone DVD players would play it. Probably the portable Mintek would play it fine, but my other two stand-alone players are not able to play +R type DVDs(these are older models). Can anyone expand on this?
Thanks a bunch! Wade