I am Ironman.
Just finished an ironman campaign. I did it without losing a pilot or 'Mech (I did have to eject twice to avoid doing so). Oddly I finished it in less than 20 hours. For my side missions I stuck mostly to battles and assassinations, and was able to acquire heavy 'Mechs relatively quickly. I also was able to get into the black market while indifferent to the pirates so stuff was cheap. After the Grave Robbing contract I was flush with cash and the black market had an Annihilator for 13,992,000 - but partial ones for only 1,397,000! And they had 6! Needless to say I picked up the parts for one then and there and came back for another a bit later.
Let me just say that even unmodified the Annihilator headcaps at almost the same rate as the Marauder!
In the final duel with Victoria, they seriously pimped out her King Crab similar to how they did the Black Widow and the Bounty Hunter. There seems to be damage reduction going on, and called shots won't hit the head. The AC-20s inflict "Devastating Damage" (that's the description that pops up, and it's damned accurate!) and the +++ Flamers are a rude shock. Finally, it won't let you get even a partial salvage.