"how this bag affects quality scans" - This 'bug' refers to single spikes in kprobe and CD-DVD quality scans that appear where a drive decouples and recouples after a write-speed-shift or a (W)OPC recalibration. These single spikes can be discounts as they do not affect the readability/playability of the disc. They happen in all Liteon drives which have Z-CLV write strategies where decoupling and recoupling of the laser takes place. I have even seen some CD-DVD quality scans of NEC burns that exhibit this 'bug' so I don't know if it is only Liteons which exhibit this attribute. So, the quick answer,"no, they do not affect the quality of the burn, just the scan".
"are scans reliable with this and other 3S Family models" - yes scans are 'reliable' to the point of that the drive is scanning/seeing what it sees at the time of the scan. Some drives scan/see better than others. These scans are just a generalization of the burn quality without using expensive machinery to judge disc burn quality.
"are 1S-5/2S Family and 3S-7 Family better for quality scans" - No one family is better than the other IMHO. There have been several cases of poor-scanning 411/811s, but in general, all should scan with generally equal ability. However, it is best to compare scans done with the same drive and firmware to eliminate differences between drives as no two are the same....in general...:).
Scanning is definitely not an exact science, particularly when using dvdrw drives versus expensive machinery designed for scanning only. if you are interested in more info, have a look at Help understanding CD/DVD Speed's "Score" , CDSpeed v3 Disc Quality Test and The Big KProbe2 Thread