I would say- what Holly said. We are using Epsilon right now, and you do need the overlays. We haven't gotten as far as Holly did, so I don't know if we will get stuck, we did have a lesson my dd had trouble with, and I just explained it in a different way than the video and that seemed to do the trick. We just switched this year and this is the first year my kids don't groan over math- and yet we do have to do yearly standardized testing for our charter school and I'm getting kind of weird about it and I just picked up a few workbooks at B & N to make sure they haven't forgotten everything else they learned and to make sure my oldest dd can do a few things that will be expected of her grade...I'm planning on adding that lightly tho, I think it is totally doable and hopefully no groans. I wrote a little review over at my blog about Math U see, here's the link,
http://homeiswhereyoustartfrom.blogspot.com/2008/01/math-u-see-homeschool-show-and-tell.html