A few observations so far:
1. The knees on mine are fine. Not so stiff as to feel like i need to break them to bend them (like Iron Monger), but good enough to keep him standing.
2. The wrist plate / hand guard on mine was stuck-on due to the paint and because its a softer vinyl piece. I used a finger nail clipper cuticle pusher thing to separate the vinyl cuff from the light post/wrist peg by wedging it in between the cuff and the wrist peg. Once i did that, the hand guard slipped right off without any damage.
3. The elbow joint is rubber which is why it doesn't match quite right. Not sure if that was mentioned already. If it was, somehow i missed that.
4. Holy crap this guy has a ton of pieces. I though my IM2 Mark VI had options. Amazing. Expensive, but amazing.
5. Of all the HT Iron Man figures i've bought, (and at one time or another, i've had them all) this guy is by far the most enjoyable to pose and switch out pieces. So far he has the best range of motion and swapping out pieces doesn't feel like i'm going to break something with every tug. Very well thought out. Even switching arms and shoulder pads was easy and didn't feel like anything was going to snap.
I hope #2 was clear. Really any flat, thin, piece of metal should be able to separate the hand guard cuff from the wrist peg.