Depends on what is available in your area.
Go and look round as many of the local state primaries as possible - we looked at 5. There are no indies in our local area so that wasn't an option.
After the first 4 I decided I needed to completely readjust my expectations of what was on offer in the State system (3/4 were OFSTED outstanding). Then I visited school no.5 and it was exactly what I was looking for. We're too far outside their 'last distance accepted' to get a place in the initial allocations I think, but I'm going to hope for a waiting list place to come up even if it takes a couple of years.
I went to a high-pressure academic prep myself and so have a good idea what is needed to have a good chance at the super-selectives we eventually hope to send DD to.
If you understand how the selective process works and are prepared to put in the extra effort and work needed then I would spend the extra on school fees for secondary.
I would never pay for any old private school just because it was private - unless I was in the situation of having a very unhappy child and that being the only possible alternative.
FWIW, none of my siblings or I ever went on the skiing trips etc - neither did the vast majority of the other students. I think a lot of 'new to private education' parents feel that they have to keep up appearances and kill themselves paying for a gazillion extras that they don't need to.
For me, education is one thing that can never be taken away from someone and so I hope to give DD the best I can. That doesn't mean the most expensive - just one where she is happy and fulfilling her potential.
If you don't like what you are getting - state or private - you can vote with your feet and move to another school.