The Figures

Left of each pic: Extremis Iron Man Right of each pic: Extremis Iron Man Stealth Variant
Above is the Iron Man based on his Extremis Armour which appeared in the comics in 2005. The figure itself however, came out in the Terrax wave in 2012. It came with the slightly harder-to-find blue stealth variant armour.
I don’t really like this figure much because of it’s relatively small size (as compared to other characters with no armour) and poor articulation (it has a decent number of points of articulation, but very difficult to pose; no waist swivel and lousy thigh swivel joint).
I also dislike how plain the back of the figures are.
Differences

Left: Extremis Iron Man Right: Extremis Iron Man Stealth Variant
They are the same exact figure except for the colour difference. That’s it. Heh.
Left: Extremis Iron Man Middle: Iron Patriot Right: Extremis Iron Man Stealth Variant
Heres the Iron Patriot from the Iron Monger BAF Wave, which uses the same body mold, except for a star-shaped chest reactor instead of round (due to Norman Osborn making changes to the armour).
Left: Extremis Iron Man Middle: Iron Patriot Right: Extremis Iron Man Stealth Variant
The back of the Iron Patriot at least looks better than the Extremis Iron Man figures.
Left: Heroic Age Iron Man Middle two: Extremis Iron Man Variants Right: Invincible Iron Man
I mentioned earlier that the Extremis Iron Man is relatively smaller in size, and this is what I mean. The Heroic Age Iron Man from Iron Monger BAF Wave and Invincible Iron Man from Okoye BAF Wave has better proportion, considering a man is inside an armoured metal suit. Both of them also has better articulation (with ab crunch, waist swivel and ankle rocker joints!).
Left: Heroic Age Iron Man Middle: Extremis Iron Man Right: Invincible Iron Man
Look at the height/size comparison! It’s a kid in the Extremis suit, not Tony Stark. Heh.
TL;DR
The Extremis Iron Man and the Extremis Iron Man Stealth blue variant are exactly the same except for the colour.
My Verdict
Left: Pizza Spidey Middle: Extremis Iron Man Right: Invincible Iron Man
I wouldn’t get this Extremis Iron Man figure if I wasn’t a ‘completist’ kind of collector. He can’t pose well and not that well-scaled as you can see above (how can a man in armour be as tall as Spider-man who is in skin-tight costume?).
But hey, if you feel like getting it, you can buy the Extremis Iron Man (Terrax BAF Wave) here, and the blue variant stealth Extremis Iron Man (Terrax BAF Wave) here.
Do leave your thoughts and feedback in the comment box below!