"My personal misgiving about HE is that it would drive me mad not to have a break from the kids."
This is my biggest concern, too. And I'll echo what Cherys has observed about HE children being over-strong in some areas and not pushed enough in areas where they're weak.
I have discussed HE a lot in last week with a friend who HEs (very happily).
She says that the biggest drawback is loneliness for the main 'teaching' adult. Beyond that, disapproval and sometimes social snubbing. So you end up feeling defensive. Also, you have to think that you give up on a lot of other options. Friend said "I gave up a lot of other things and dreams when I decided to HE."
And many people simply couldn't afford to HE, or not without making (for them, and maybe for anybody) unbearable financial sacrifices.
Also, HE friend has children who help out frequently around the house (sigh). She considers it a pact with them, she couldn't do HE without their help. Else she'd end feeling like their skivvy (as would I). I can't see my DS doing household chores just so that he didn't have to go to school. The whole helping-out thing would just turn into another horrible feeling battle zone (we have tried to improve DS attitude on this one, believe me ).
Parenting with precious little support (which is what I do) is hard enough. But HE without precious little support must be even worse.