There are so many reason that we chose homeschooling: better education, better socialization (interacting in the real world versus the negative socialization that occurs in schools--bullies, etc.), bonding more closely as a family, and trying to ensure that my kids keep their love of learning instead of rote memorization and teaching them how to ace a test every year. My kids learn so much about the world from playing in the backyard, from doing science experiments at home, playing educational games, in addition to the workbook pages and reading we do. The kids can work at their own pace of learning (my 6-year-old is doing some second grade work, and my daughter is doing third grade work). We attend a weekly homeschooling parkday group, and the group also has field trips and moms organize other activities for kids to participate in. The kids avoid the negative socialization from schools (bullies, peer pressure, etc.), and socialize with other homeschoolers and us. I love being with the kids all day and watching them as they learn, and being directly involved with the process of their learning.
When we first decided to homeschool, I was a little nervous about it. I was in public school my whole life, and always heard the idea that homeschoolers were not "socialized" which worried me. But the more research I did, the more I was convinced that homeschooling gives them much more positive socialization than being in a classroom all day. One book that really convinced me is called The Well-Adjusted Child: The Social Benefits of Homeschooling by Rachel Gathercole. She points out how children who are homeschooled have so many opportunities to socialize (taking classes, participating in community activities, forming close bonds with their parents, friendships with other children, etc.), and are able to socialize with a variety of people, not just other children their own age. It's a great book, I highly recommend it.
And do other research, too; there are tons of resources out there to help you figure out what works best for your family. I found that the more research I did, the more I was convinced that it is the best for our family, and the best for the kids as far as learning goes. As far as the program that you are talking about, it sounds like a great one: there is interaction with other children yet most of their learning takes place at home. I would say that it depends on how much independence you want for homeschooling. Some parents (like us) love having the freedom to choose what we want to teach our kids and when. We decide (the kids, too) what they want to learn about and we gather our own materials to learn about it. Other parents like to do a formal curriculum, where you enroll in the program and the program sends you the materials and tells you what to teach and when. Many parents like this because they like to follow a guide and it helps reassure them that they are teaching the "right" things. Most people, I think, are somewhere in between, and many families choose different homeschooling approaches every year depending on the needs of their families.
Sorry this is so long; I just love homeschooling our kids and always like sharing our experiences with anyone else considering it for their own families. All pros, no cons (of course, I am slightly biased). :-)