What? What are your definitions of FAI and unfriendly AI?
Artificial general intelligence (AGI) = any intelligence with near-human capabilities of learning and innovation
Friendly AI (FAI)= an AGI which understands human values
unfriendly AI = an AGI which is not FAI
FAI will be harder to develop than unfriendly AI, but the question is how much harder?
Reasons why FAI is harder than AGI have been extensively discussed by Yudkowski and others. These include:
Human values are hard to understand
The growth mechanism of FAI must have low variability to ensure that the FAI remains friendly. But high-variability growth mechanisms (such as mutation and selection) could be the easiest path to AGI.
FAI will be harder to develop than unfriendly AI
Doesn't this conflict with your other statement?
the easier it is to develop FAI in comparison to unfriendly AI
Let's take for granted that pursuing FAI is the best strategy for researchers interested in the future of all humanity. However, let's also assume that controlling unfriendly AI is not completely impossible. I would like to see arguments on why FAI may or may not be the best strategy for AGI researchers who are solely interested in selfish values: i.e., personal status, curiosity, well-being of their loved ones, etc.
I believe such discussion is important because i) all researchers are to some extent selfish and ii) it may be unwise to ignore researchers who fail to commit to perfect altruism. I, myself, do not know how selfish I would be if I were to become an AGI researcher in the future.
EDIT: Moved some of the original post content to a comment, since I suspect it was distracting from my main point.