Pates is the best school in the county and if you want the best education go for it ..
That depends how you define 'best'. It may be best for some children, yet for others of grammar ability that may not be true. Not every school is right for every child. Some might define best as including distance from home, other as pressure on the child, others the facilities the school has and others as score in exam required to get a place. Parents who already have children there may be slightly biased, as that's the school they chose for their child (so they must be right).
However, I would say that it is a very good school, from my limited knowledge. I'd encourage all Y5 parents to look at all the reasonable options and see what they offer. You might be surprised, or your preconceptions may be confirmed.