I purchased Math without Borders a few weeks ago. We switched from Math U See. MUS is fine for the elementary math, but the high school math was lacking. I researched lots of reviews on Algebra programs and liked what I read and saw at MWB. I have switched my now 9th grader to MWB and will do the same as the rest of my children start algebra.
My 17yo used MUS through Pre Cal and placed into college Pre Cal, but we started her in College algebra. She said that there is a lot of stuff that she never encountered in MUS as she was taking the college class and on the SAT. She loves math and so it wasn't difficult for her to figure it out, but she begged me to get something else for her sisters.
So far, we are pleased with MWB. The lessons are very informative and thorough without being too wordy. As a homeschooler, of 6, I usually run from anything from the Government school system, but I decided to give it a chance. I figured that if the book has been around since the early 80's that it must be excellent and worth a try. I also have to say that the price was right.
I let you know more as we get further into the program.
PS Sure would love a great Calculus program.