My son is only 7 (he has aspergers) and has never been to school, but maybe our experiences might help you in your decision. We decided to homeschool after Deuce was asked to leave daycare at age 2 because he just wanted to sit in a corner and play with a truck (all day, everyday-not wanting to play with other kids) and then asked to leave preschool the following year (I thought maybe he'd matured enough to handle school then). We had other reasons for homeschooling, but this was what made us start considering it.
With homeschooling Deuce can work at his own pace (fast in some subjects and a bit slower in others), and doesn't have to spend 7 hours a day on schoolwork (unlike children at public and private schools). Because he has so much control over his day (which is more like adult real-life than the school where he would always be on someone elses schedule and agenda), he has very few 'issues'. It has gotten so much better as time has gone on. He takes extra-curriculars based on his interests (martial arts, scouts, art class, gym class, etc...) and makes friends in these activities based on the shared interest. Only 1 of those activities (scouts) is divided up in the same manner as school, with all of the kids being in 2nd grade. The other, mixed age and gender classes, mimic real life better and prepares Deuce for dealing with people of all age ranges.
I couldn't imagine putting Deuce in school ever because I know how well homeschooling can work. It's not always easy (some days he just needs time alone, so we have to come up with activities that he can do by himself, like independent reading), but it is so worth it. He has been the type to get brutally picked on by local ps children before and I wouldn't know whatt to do if he were faced with this all day, everyday. It's also nice because I get to be there for all of those great 'aha!' moments. when he finally gets a new concept that he has had trouble with.
If money is a problem (I know that some hs products can get pricey, especially for older kids), you might look to see if your state offers a virtual charter school. They provide the curriculum and a computer and the child works from home. This also provides more accountability for the parent (or child) that needs that type of accountablilty to stay on track. K12 has free charters in many states and so does connections academy. You might try looking them up.
I have some links on my blog that might help you (curriculum, HSLDA, some homeschooling forums that have special needs forums, etc...) http://www.homeschoolblogger.com/sisterchicksteph
Good luck on whatever you choose! You know your child best and will know what feels right for your family- just trust your instincts!