^ I agree too... at first hearing the colabs... I didn't care for them, but after a while I find myself singing along with them in the car... lol. And I claim to at hate that Natura (what his name is) guy... lol... he is growing on me
As for the best ever? I don't know... I love FIVE, but you can't really compare them to other albums because it's not an album... the diversity isn't there because there's not enough material to compare. Personally I think I love old ayu better... (to me her peak in music excellence was Duty to I am, maybe Rainbow because I like to include memorial address into it...)
But the stuff she is doing now is just as good, different, not "old ayumi" but still good.