It seems to be the case from user's reports. When I asked for opinions about the 3540's ability to scan before buying one, I've been told "depends on luck" LOL
mmm I wish that I had realised that before that I bought one, but then again if I did would I have done anything different...? I doubt it
At least though by realising that the drive could have a scanning problem wouldn't have made me too concerned about the quality of scans that I'm getting.
For what I want to use the bulk of the discs that I write for longevity isn't the most important factor. Playability wise has never been the issue as I have DVD's written at 8x with my 2500 for a couple of years and they have been no problem in several stand alone players, with the cheapest of media.
Our DV movies, from my Camcorder, are always backed to DV tape AND expensive DVDr's written at a slow speed.