I just made the upgrade to this firmware on my 24102B and had to test the SD2 back up abillity, and I must say that the first thing that I noticed was the burn was a lot more consistant. (even with cheap smart buy media) The next thing that I noticed is that my back ups tend to load a little quicker now. Not sure if there are any bad points to this firmware as of yet, but I am sure that is there are any that it will be posted soon enough.
So far I have to say that I do like this firmware. One more thing that I noticed is that for some reason or another my 24102B was running in PIO only mode and would not make the switch to DMA till I made the upgrade to the 5s59 firmware, and I must say that it is a noticeable change with the drive running in DMA.