A couple threads that illustrate some things I like about Cold Iron
Or at least the way I use Cold Iron. Threads on Monte Cook's ezBoard:
A major sub-topic in the first is statting up NPCs, and shortcutting by just inventing a couple stats. The second has several posts that talk about making combat more interesting by inventing new monsters.
In the first case, Cold Iron's combat stats are simple enough that it is reasonable to use the correct derrived stats and not just invent stats. And with my handy monster skill cheat sheet, I can whip up a set of combat stats in a few minutes.
In the second case, people are trying to regain the fun of that very first D&D session where you had no clue what an orc was capable of. People try and regain that by inventing new monsters, or twisting old ones. But basically, this amounts to Calvinball. And it's not necessary.
One of the most enjoyable encounters in my Cold Iron history was a necromancer and his horde of typical undead. The same undead stats I had been using for ages. But with a twist, not invented, but taken straight from the rules. See, I realized the necromancer could easily afford to create anti-magic shell charged items for every single undead minion. It was really fun watching the players deal with these simple ghouls - that they couldn't hit with spells (well, at least most of them - many of the ghouls weren't protected because the items failed to activate).
While I have about 50-100 creatures written up for Cold Iron in various forms, the reality is that 90% of the encounters are run from a very small subset of this list, probably 20 creatures. And because the combat stats are fairly simple, and don't have lots of extraneous stuff (I mostly just figure out Size, Str, Dex, and Con for monsters for example), it's really quick to stat them up (and when they need to make saves, for example of a less used stat, 90% of the time, it seems like, I don't need to figure out their save because the roll either clearly makes it, or clearly doesn't make it - now perhaps sometimes I wing those).
Another factor is that I only run meaningful encounters. So I don't need stats for the thousands of people in the city. Because the PCs aren't going to fight them. If they're just talking to them, I'll be saying yes. Or when we roll the dice, it will probably be an unopposed roll. And if they decide to kill a street urchin, I'll probably just say they dispatch him, and if I'm mean, I might roll 1d6 of damage for the PC or something silly like that (really no need to do that kind of thing - but that was one way of handling insignificant encounters in the past).
Of course all of the above isn't specific to Cold Iron. Rune Quest was also similarly simple. I admit that I get trapped by all the monster manuals for D&D. But what D&D doesn't have is a good quicky way to write up a monster (and with the CR system, it would be really cool to provide a variety of "generic" monster stats - a CR 5 "tank" might have AC 20, 50 HP, Attacks 2x +8 1d8+8, 1x +3 1d6+4 or something like that).