After having the release being pushed back by 3 months, it seems the entirety of the Max Factory Big O line is on the shelves. Including my own.

I only purchased Big Fau, and I'm rather glad it was just the one. The thing is MASSIVE, and its box is huge. I can only imagine how wide the Max Factory Big Duo stands with its enormous engines. In height order from smallest to largest:
Kotobukiya Mini-Figure "Big O" (3 1/16"), Bandai
Anime Collector series "Big O" (7 1/2"),
Soul of Chogokin GX-48 "Big O" (8 3/8"), and
Max Factory "Big Fau" (12 1/4").
The only joints on the model (which is quite light) are at the neck, shoulder, and femur/hips. They're a basic swivel on one plane... for the cost of one Soul of Chogokin Big O, it's only "alright". From a distance (on display) it's a great thing for the Big O fan to show off. Close up (modeling) the details could be better and more of them. It's definitely a "for show" model rather than something the traditional model collector would want in this day-and-age.
Let's put it this way: while I'm not completely disappointed in the purchase, I will sell it in a heartbeat if Soul of Chogokin announces Duo/Fau for 2012/13.
With that said, the Max Factory 2011 Big O model (which is fully posable, includes all his accessories, and is triple the cost at US$400+) must be absolutely brilliant. It's probably the closest thing to the toy the show was originally meant to sell (it's big enough) but that price tag is so prohibitive it's not even funny.