R.J.
One thing to keep in mind is that out of the several hundred HS'ers I know in real life, and the several thousand from online, only a TINY fraction "pick" a curriculum and stick with it.
In fact, it's the most lamented thing in the HS world... how much money is wasted on curriculums the first 1-2 years.
Checking out the RC website, this is one of the things that makes me nervous about their curriculum. There are no demos, and there is no return policy. Which is abnormal in the HS world. HIGHLY abnormal. The vast majority of all curriculums WANT prospective parents/teachers to be able to get a real feel for the curricula themselves AND to be able to "test" it out with their children. Which is a BIG deal, and a common theme in HS'ing. One of the real benefits is being able to tailor an education to suit a particular child and family. I can't count the number of times I've been excited about something, start to introduce it, and realize that it is not a good fit for my son. ((We're eclectic HS'ers, so I sift, sort, and use a vast array of different curriculums and pieces of curriculums)). Or, same token, are already using something that works very well, and stumble across something that is PHENOM, and kiddo's abilities and excitement just skyrocket using a slightly to completely different approach.
Ditto Saxon Math is one of the more popular maths programs. The top 3 would probably be Saxon, Singapore, & Time for Learning (I mention T4L a couple times, but we don't use it... we use a combo of Singapore and Montessori). The idea that ONLY Saxon math can/should be used for self directed learning / child led learning I find to be fairly preposterous. Esp. when it's one of the more Teacher-Intensive math programs.
Another thing that makes me a little nervous about the RC, is the whole assertion of "this makes child led learning possible". Child led learning is not a new concept. In fact, in the vast majority of HS'ing, it's the overwhelming theme that spans several philosophies. Montessori, The Well Trained Mind, and Unschooling are probably the most well known of all of the child-led philosophies (vastly different approaches and application to the same concept), but even in teacher led philosophies there are a lot of child led concepts. ALSO, all of the interactive computer programs (from Time for Learning, to CyberEd, to games like ClueFinders or reading programs like Starfall.com), there are LARGE elements of self directed/ individualized pace/ parent is not actively teaching their child.
Anyhow... just some things to think about.
To get an idea of what is considered more "standard" in curriculum buying/purchasing (as in demos, price, and return policies), a handful of the hundreds of FREE curriculums, & philosophy application check out the following websites:
http://www.homeschoolbuyersco-op.org/
http://www.homeschooldiner.com/
http://www.freemontessori.org/?s (check out the Albums link on the right)
http://simplycharlottemason.com/basics/started/charlotte-... (with straight CM all one really needs is a library card)
http://www.noeoscience.com/
http://montessorird.com/index2.php?cPath=1&osCsid=0sc...
http://www.lessonpathways.com/
Anyhow... just a handful of things. Also, a resource I've found phenom over the past couple of years are the Yahoo homeschooling groups. Hundreds to thousands of HS'ers at your fingertips. A groups search of Homeschool and _________ will yield a lot of results. Not knowing if you're religious or not (I'm not) here are a couple to start off with; some are religious, some aren't.
http://groups.yahoo.com/group/secular_homeschoolers/ ... general secular board
http://groups.yahoo.com/group/AHomeschoolReview/ ... curriculum review board, christian bent
http://groups.yahoo.com/group/playschool6/ ... montessori homeschool board, catholic but inclusive
http://groups.yahoo.com/group/SecularCM/ ... secular CM board, all faiths welcome