Since I am getting my very own Nexus One soon (yes yes, tomorrow, tomorrow!!!) this article of course caught my immediate attention.
The OLED-Association responds to the Internet chatter that was going on after one well-regarded tester (DisplayMate) and one blogger (DisplayBlog) compared the AMOLED display in the Nexus One with the LTPS LCD in the iPhone. In short, according to the tester, the AMOLED didn’t measure up.

I invite you to read the full report (link below), it actually is a good read and even though the OLED-Association is by definition subjective, they did a good job in pointing out some things.
For those of you that don’t have the time to read the rather lenghty article, I am including the conclusion of the response here:

According to his report, Dr. Soneira tested only the 5-6-5 color depth mode and he did not use or perhaps figure out that the display had an 8-bit capability. Therefore, it would appear that the conclusions are based on some incorrect assumptions.

The work that Dr. Soneira has done is important and I urge him to ensure that he understands how PenTile technology works by talking to its inventor, and to redo the tests invoking the 8-bit capability the way the display was designed. Moreover, we should use this situation as a teaching moment.

If in fact the AMOLED display has flaws and it just may, Dr. Soneira would make a great contribution if he could identify the causes of the problem by disaggregating them:
The selection of materials in the OLED.
The PenTile display architecture.
The way the gamma curve was implemented. For example, OLEDs and LCDs benefit from different gamma curves (due to the psychovisual properties of the human vision system in high contrast dark images in OLEDs versus the low level brightness of an LCD), so indicating that the OLED doesn’t perform the way an LCD does, is not necessarily an error.
Implementation of how the multiple gray scales are selected.
Hopefully, this would shine some light on what causes the performance differences between the OLED and the LTPS LCD, which one is better and how it can be resolved. Condemning OLEDs, PenTile or the driving scheme is no longer sufficient, given the system level considerations of overall phone properties, interactions of the components and especially when so many users appreciate the viewing experience.

I can’t wait to be able to make my own comparison tomorrow (yes yes, tomorrow tomorrow!!!)

Source: Oled-Info