I'm in an infant/junior area, but come from a primary school area.
There's advantages and disadvantages I think. It may depend on your child as to what suits them.
I remember listening to one of my dcs talking with friends. They'd just finished the Spring term in reception. They were already talking about "when we go to juniors". There was no linked school so they already were aware that they might well not be at the same school in just over 2 years time.
For one of my dc, who struggled with the change going up every year, she would have been better at a 1 form entry primary (like I was at) where you didn't just know which teacher would take you next year, but probably the one after that too (and possibly all the way up!)
For one of the others, they thrive on change and it was much better for them, especially as it meant they could get away from a child they had had problems with.
There's nice parts like the year 2s getting the feeling of being the oldest year with some responsibility, and I think that they got more opportunities due to that.
There's also that the school is set up more for that age, so things are targeted more for them.
And some people feel that the larger junior set up helps with the transition to the (very large) secondaries.