Immediately, M.I.C. must be compared to Border Control. Isolating strictly their trash effect and cost, Border Control is superior. It ends the run without any conditional and only costs 4 to rez. Comparatively, M.I.C. allows the runner an out for a and costs 2 more at 6. Therefore, we must look elsewhere to justify its use.
Out of faction, it is a single influence point cheaper which so far would only be relevant 50% of the time (if you are NBN or Jinteki). In my opinion, if you thought it was important enough to spend influence for an effect like this in the first place, then the 1 extra influence pip isn't even a contest--I'm spending the 3 influence to get the guaranteed effect as opposed to a "maybe" effect at an increased 2 cost. Add to this that NBN and Jin don't naturally tax runner clicks in the first place and it seems likely the runner would have the click. So again, we must look elsewhere for the justification.
So now, let's look at strength. Where Border Control succeeded in being a nice little gear check that refunded a bit of its cost against the faceplanting runner, it failed as a taxing piece of ICE at the mid game and beyond, once the runner had basically any way of breaking a single barrier subroutine. Paperclip, long our standard Fracter-measuring tool since it replaced Corroder, breaks it in 2 (with the option of just 1 if you don't care that the corp makes a bit of ). Most others will also bust it in 2 or 3. M.I.C. shines a bit here since it sits 3 strength higher at 4. Using the tried and true Gordian Blade as our template, we now have to pay 2 just to boost to match strength, plus another 3 to break the other subroutines. Of course other decoders will fare better or worse against the 4 strength 3 sub values, but you can already see that generally it's a more taxing piece of ICE. But there's one last bit.
The clever runner will always manipulate a run into their favor as much as possible and so may run on their last click, choosing not to break the first two subs. After all, you can't lose clicks you don't have. Suddenly we're back to breaking this for 3 which is almost as bad (or as bad breaker-depending) as Border Control. But of course, this is precisely the spider's web that good Code Gates create--a choice, a gamble, that the runner must choose--for in losing all their clicks, they open themselves up completely to the trash effect of the card, and therein lies M.I.C.'s strength.
You see, a runner that lets the first two subs fire is either desperate, or doesn't really care if the ICE is trashed to prevent the run. Which means you as the Corp have but one choice: make them care. Include taxing upgrades, agendas and other effects that ruin their day regardless of whether they let the run end, or whether they spend the click. Use it to stop their game-winning push for victory by providing them a catch-22.
And there resides our justification. We include M.I.C. when we want to tax the runner more than we do with Border Control, and when we want to play -intensive mind-games with them to close out the game.
The best thing is that the investment is really cheap.
— valerian32