It depends. How much do you want to spend on a diet?
The article you link to has some points which have been made by other blogs (usually competing diets) but the key is what they don't mention in those articles.
1. You pay for Weight Watchers. For some people, this is an incentive to stay on the diet. For others, it is a deterrent to even join, or to stay when they don't lose at a rate they like.
2. There's nothing magic about the points system. It's just counting calories, but it steers the WW member in a direction that encourages more fruit and vegetables and less fat. The 'less fat' part is standard for any calorie counting diet, just because fat has more than twice the calories of protein or carbohydrate. Also, studies that show the effects of high fat diets are still being produced - long term results are the issue with WW. The WW diet is fairly conservative. Fruits and vegetables are considered healthful by any measure.
3. I myself love WW. Theirs is the only weekly weigh-in I trust. The scales they use are calibrated carefully and the weigh-in takes place behind a screen or barrier. Also, there is definite accountability when they record your weight online and in your 'passbook.'
4. The face-to-face contact with other successful WW is very important. Every meeting will show some success with the diet, often small successes over time, sometimes HUGE success that is very visible to the other members. There is no need to be public with your results but there is recognition at meetings when a member reaches his or her goal.
5. WW is flexible. There are vegetarians and flexitarians and pescatarians and every other kind - there also is no WW law that says you have to declare how you eat every meal or what choices you made every day. If it helps you to explain in detail how you lost those 5 pounds, fine, if not, fine.
6. There's a ton of support with literature and the website really keeps up with your measured progress. If you pay (extra) for the online access - it's affordable IMO - then your weight at weigh-in shows up immediately when you login. It stays there as a record of your efforts. Although the WW cookbooks have just gotten better over the years, the old WW cookbooks are great sources of every kind of meal or food you want to prepare. If I recall correctly, the recipes online are very good, too. They also send an e-mail newsletter.
7. The biggest criticism of all - that WW has ____% failure rate has the biggest flaw. WW does have lots of data. Other diets do not, and frankly, it's not in their best interest to bother. Study after study (not funded by WW) have shown that group meetings and steady check-ins with accountability and food journalling make for weight loss success. This means that Fitday works fine, too - if you go to the forum and join a group and stick with it. Other groups have this advantage, too - but you don't always have to stick with it and you don't always have to check in. There you actually LOSE an advantage.
8. WW help you to achieve your goal. When you've achieved your stated goal, you earn the free support that follows (it's limited but it's there in the form of weigh in and followups) so that you can maintain your success or at least regain your success. Member meetings usually have some lifetime members (who've attained their goals and maintained) so that can be very inspiring - or not if you just don't care. But this is all very visible and it is simply not there, not visible, with other diets.
I can't speak for Overeaters Anonymous, which is similar -and cheaper. But WW succeeds IMO for the reasons above. The criticisms will always be there. The data from millions of long-term members and recorded data also will never be there for competing diets because the WW model is fairly strong and so far, legally, you just can't touch it. The Points system doesn't make calorie counting harder, it makes it easier. That system can't be duplicated because I believe it is copyrighted or trademarked (whatever the word is that applies....) for good reason.