GreatSchools.org (our take)
http://GreatSchools.org is the easy-to-use, test-driven school listings resource visited by one-half of U.S. K-12 families (55 million users).
The compilation includes test scores, demographics, and increasingly, SAT scores, college readiness, and growth ratings, and actual parent reviews. Test scores, traditionally have correlated to parent income, and has caused some folks to question their reliability. As more data becomes part of the equation, scores will change, and some folks will question those numbers as well. The bottom line is that no one can tour every school, and no one should rely simply on test scores, or even make a hard cut off such as looking only at 9s and 10s. As LAUSD is loathe to break out magnet scores, many scores are blurred between the magnet and resident populations. The bigger the difference between the magnet populations and the resident school families in terms of economics, home language, etc, and the scores are not going to correlate.
GreatSchools also offers a checklist on what to look for on a tour: http://www.greatschools.org/gk/articles/the-school-visit-what-to-look-for-what-to-ask/
Suggestions for smoothing the transition to middle school: http://www.greatschools.org/gk/articles/smoothing-your-childs-transition-to-middle-school/
And, they even help explain their methodology and what it means: http://www.greatschools.org/gk/articles/what-average-greatschools-ratings-mean/
Many of our own kids, and kids we personally know (some gifted, some special needs, some reading three grade levels ahead) are thriving in public schools they love with GreatSchools.org ratings of 6, and even 4 (that’s on a 10 point scale). They’ve graduated on to the UC’s (and yes, even Harvard) and succeeded academically without throwing their families into hock. So we suggest you use GreatSchools.org not as your FINAL arbiter but as one tool in combination with visiting schools and candidly networking with other public school families.