If you're looking for something that will bring you out in a sweat and get your heart pumping, then this isn't the workout for you (try Nell McAndrew's Maximum Impact or Kate's Cardio Combat), but if you're someone who wants a gentle, fun workout and you're quite co-ordinated, then I think you'll really like it.
It's a nicely structured workout, with the five short sessions giving you lots of variety. The first two are fun but do require a bit of following, partly because the camera work is distracting (a lot of the time you can't see the moves because the camera man is either too far away or practically up Zoe's nose) and partly because it requires a fair bit of co-ordination and more dance type moves than most workouts. The Box and Tone sections are very effective and definitely the most challenging. The cool down Yoga section is fine and will give you a good stretch and leave you feeling nice and relaxed.
The great thing about this work out is Zoe and her trainer. They are great fun, really enthusiastic and look like they're enjoying themselves, it's almost like working out with friends. But, as a regular exerciser, I found this workout wasn't hard enough for me and I only keep it for days when I can't face anything too challenging and want a bit of fun, relaxing, gentle exercise.