Of that list, I've only tried the VIP Super Soft and O2 Mark.
I did, however, buy Super Soft versions of Mikey, Adam, and Mark directly from Tantus when they had some on clearance for cheap (I think $19 each.)
I liked Super Soft Mikey, but it's pretty thick. The Super Soft Adam and Mark were way softer than SS Mikey and VIP, to the point they were not even usable - a complete waste.
In any case, knowing the size of Mikey, I think the O2 version would be too much with the added firmness of the inner core. Mark was too small.
So I vote Adam, and will probably try that in the near future.