Air Law, without a doubt, then Met.
I found all the others easy because I had come across much of the information before or had an interest in the areas before.
The Confuser was very useful to understand the format of the exam, but I agree it can be "abused".
Regarding Nav, if anyone is interested, I am sure I can dig out a piece I wrote on why the "jiggle" method is employed using the wind-side on the CRP1
Recommendation from someone who nearly found himself in flyingwysiwyg's position: "Do one exam a month" - wish I had, it would have made the last 3 weeks much less frantic!
Actually, you now have 18 months to complete them all (does that include the FRTOL?) so you can comfortably make that one every 2 months!
Cheers
SD