I have been teaching the GED for 20+ years, and I insist that each of my students own this book. First of all, it breaks down the basic math skill areas into clear steps with helpful examples. Then it gives the student lots of opportunities to review what they have learned and assess their growth with mini-tests after every 3 lessons and unit reviews. Also you can practice for the GED by taking three full length practice tests. The answers and explanations in the back can help a student learn from their mistakes. Best of all, the level of difficulty matches the actual GED pretty closely (not true of other publishers) so if the student can do well in this book, you can expect that they will do well on the GED as well.
My three complaints about this book are:
the chapter on percents is confusing. There is a much better way to teach percents that asking students to memorize and manipulate a diagram.
There needs to be more on charts and graphs, which are getting bigger and bigger on the GED. Also I wish there were more on ratios & proportions. I always find that I have to supplement the book when I get to this lesson because SV gives us very few word problems, and they are all too easy.
There should be a bigger section on multi-step problems, also another huge area on the GED. SV is great for breaking down the test into skills, but sometimes questions ask you to work more than one skill at a time.
SV Math can use improvements, and I would supplement it with some of the newer stuff from Contemporary (another publisher of GED books) but as a basic GED math text, it really is the best book out there. I highly recommend it.