Nigel Lythgoe is a judge (and executive producer) on So You Think You Can Dance, and this review is based on his appearance there.
It seems to me that Nigel is filling the required "Simon Cowell" spot as a judge in a reality/talent show. I don't know why this is necessary... except that it is. Someone has to be realistic and a little nasty. Not everyone can do that; Simon certainly can, and so can Nigel.
I don't mean that as a bad thing, either. It's good. Someone has to be realistic after all the gushing is over, and Nigel does that well. He's not as nasty as Simon is either, which is good, but he's honest, and tells the dancers what he thinks. He's usually nice about it, but sometimes can be abrupt and to the point. But that's needed, so that's good.
And he can be nice too... this season (2006), one of the contestants hurt herself in Las Vegas, and had to drop out of the competition. Nigel told her that she could come back next year and skip the initial auditions, and just pick up where she left off. He didn't have to do that at all... he could have just said, 'oh, well, that's the dancing world for you... you get injured and you lose out! Bye bye!' But he didn't do that; he was kind to her and gave her another chance to try again after she's better.
Overall, I like Nigel for his honesty. He's a good judge and should be on more shows!