Strange that you should experience that. koland from this forum says
here on her site in the second comment that the Kobo wireless's screen is about as good as a Kindle 2 or Nook.
The common wisdom on mobileread seems to rank screens in this order:
1. Pearl screens, i.e., K3, PRS-950/650/350, with 350 slightly above the others because of greater ppi.
2. K2-era Vizplex, like Nook, Kobo, etc.
3. Earlier era Vizplex
Somewhere in the above are the Ectaco LCDs.