I run press, so I'm very interested in finding recruits that ran that defense in high school, unless my plan is to redshirt them their first year, in which case it doesn't matter because they'll be coming in as a C or better after the redshirt year anyway.. Offensively, it's nice if they ran what I do, but I really could care less. The impact of offensive IQ, from my vantage, seems significantly smaller than the impact of defensive IQ.
That said, it isn't a make-or-break thing for me. If I find a recruit that I feel is noticeably better than my No. 2 choice at that position, I'll go after him whether he has IQ in my systems or not. It takes about 12-14 games to raise an F to a C with 20-25 minutes of practice time (depending on "how F" the player was, HS GPA, etc.), so really you're only looking at a guy's freshman non-conference season and the first couple conference games before he's a C or higher. For the right player, I'm more than willing to make that tradeoff.
Where I do use IQ is if I have a number of fairly similar choices at a position. In that case, the scholarship offer will go to the guy with the best IQ fit to my program.