Previous studies have shown that various ab-gadgets are no more effective than crunches, and some are less effective than crunches. I haven't tried the ablounger, but it looks very gimmicky. Maybe one of our fitness experts will have an opinion on it. I would recommend a balance ball, though. ACE Fitness (American Council on Exercise) did a report on ab gadgets a couple of years ago, and they showed what worked and what didn't work. In a nutshell, none of the infomercial type products worked. They suggested crunches on a balance ball (10 bucks at Walmart), and gave some tips for traditional crunches.
http://www.acefitness.org/getfit/abstudy_top.cfm Consumer Reports did a follow up on this and also suggested the balance ball. The ball may support your lower back better.
Keep in mind that the people in the commercials are actually fitness models that make a living promoting these products. They work out in gyms, may have professional trainers, and don't represent the average consumer. It's very easy to make a product look attractive.
Based on general comments I've heard from others: The ablounger might encourage you to use it at first, and appeal to the person that does not exercise regularly. However you would probably grow out of it pretty quickly. I've yet to hear from someone that has had noticeable results from it.