I'm very much in the early stages (2 toddlers and baby on the way) and my key motivation in deciding (tentatively) to home-ed is that I think children start formal education way too early in the UK.
I have a theoretical plan I'd like people to critique (as harshly as you like - I'm genuinely looking to challenge and evaluate my ideas). It is to home-ed until 7 definitely. Then start looking for a school place in a school where I like their approach to learning according to the character and readiness of my child. So it may be they start integrating into junior school age 7/8, or it may be 9/10 - whatever suits. Just not being fixed about it.
I taught junior age for 10yrs and I know there are some great advantages to being in school as well as some serious down-sides. I want my kids to experience those advantages without risking having had love of learning, confidence and sense of self die away due to constant assessment, learning environments that just don't suit them etc. But I do want them to have the option of being very academic (dh and I were) in an academic environment at senior school or beyond. Or very sporty (dh & I have no clue!). Or whatever they want, in an environment that suits them. Integrating at senior age seems harsher than at some point during juniors.
My impression is that I'm kind of doing the opposite to most people, so I'm really interested in debating this one out AND hearing of any personal experiences that are relevant.