Well 4x IMO covers up many imperfections of the discs, seeing as most liteons are great readers and going at 4x is just going to make it easier to read the disc.
This is my method for testing using a liteon:
4x with jitter
16x PIE/PIF test without jitter
A DVDScan to see how the pits and lands look
Just 4x without jitter IMO is not giving you much of an insight to how well the disc is actually burnt. CDFreaks however, tend to think that 4x without jitter in K-probe is a good representation of quality. I would not trust their reviews, instead I would search the forums to see which drive burns with the lowest errors and lowest jitter.