"This is the thing I wonder about homeschooling. I realize this doesn't apply so much in the younger grades, but as a kid gets older, what about being taught a subject by a teacher who really KNOWS that subject inside and out, versus a parent who may be one chapter ahead of the child in the textbook?"
This is the one fear I would have of homeschooling, but the availability of information on the internet is astounding. The parent just needs to familiarize themselves with good education sites (.edu, .gov) versus bad sites (typically .com .org, although there are some good sites if you are careful). And when you add in the multimedia capabilities, the internet is a strong resource, if used properly.
The other disadvantage would be availability of lab equipment for the home schooler, but apparently some of these home-schooling groups have their act together.
"Recollect me darlin, raise me to your lips, two undernourished egos, four rotating hips"