Hi - I've got it. DD is 9mo now, and I've only recently started using it, and I find it really really tough. I think personally (and I have no qualifications in this area whatsoever!) that it would be stupid to do it as soon after giving birth as she suggests - ie 6 weeks after giving birth "as soon as you are released by your doctor", as she keeps saying. Depending on the kind of birth you had, and your physical state afterwards, I think I would have been in tears if I'd tried it. The abs bits are hard! And I reckon it would have irritated my stitches, and so on.
I find her deeply annoying, and she doesn't explain everything that well, doesn't always give an easy option for beginners, and if you aren't watching the screen the whole time she sometimes changes exercises without saying.
However, it really does work, and I now do it with the volume down, and pause sometimes when I can't keep up. I also skip one of the abs sections with loads of planks, because it makes me cry a bit.
I reckon if you were reasonably fit beforehand, and you aren't trying too soon after any kind of tricky birth, then it's great for results. Otherwise I'd steer clear.
Ellesabe - I think the difference with this one to Tracy's others is that it is in theory gentler (ha!), and focusses way more on abs, as I guess that's the bit that needs most work post natally. Other than that it's actually pretty similar.