Westminster School. Is it really that good?

I read a lot of great reviews about this school, they have 97 places for their students at Oxbridge this year. My son is good academically speaking but I'm not sure he is outstanding. He is 7 though, and I'm pretty sure if he really wants to he can get there. So my question is - is it worth the pain and the money?We do want him in Oxbridge eventually, it is his dream too. But I know there are other good schools that can help him get there as well. Any thoughts are welcome.