I'm a huge fan of the 10 Minute Solution Pilates DVDs and the latest, Pilates on the Ball, is an excellent addition to the series - the most intensive workout of the collection, due to the extra effort required working with the ball.
There are 5, 10 minute Pilates ball workouts, on abs, upper body (arms and back), lower body (legs and buns), a total body workout and a stretching session. I always start with abs to get my mid-section warmed up ('the powerhouse') then choose at least 2 other workouts, sometimes doing all the sections for a very rewarding 50 minute workout.
I would say this is aimed at an intermediate/advanced level, however with practice, all the moves can be mastered. It looks really easy, but when I did it for the first time, I was laughing so much as the ball kept escaping from me, but within a week, I had got in under control, yay!
Lara Hudson is an excellent instructor, giving clear direction and breathing cues (could have done with more of those) while always praising and encouraging your efforts. There are new twists on classic Pilates moves, and you will really work hard to hit all the targeted areas with some innovative and challenging movements. You'll have fun (diving over the ball is great for your inner child!) and feel the burn at the same time.
In summary, you get straight down to it, not a second is wasted and you will benefit from each intensive and fluid 10 minutes. So many muscles groups are worked at the same time, in each workout, so even though you are say, working your lower body, because your muscles will be concentrated on keeping the ball under control, you are getting an intense workout in other areas too, bonus!
If you like this, I would recommend checking out the these other 10 Minute Solution's Pilates DVDs: 'Rapid Results', 'Perfect Body' and 'Solution', all excellent. I've been working out to these for nearly a year (along with doing cardio) up to 6 times a week, and can definitely see and feel the results. In addition to working towards a leaner and more sculpted body, your posture will improve and you'll learn breathing techniques which really help with relaxing - what more could you ask for!