Exante is great in terms of not having to work it all out, calculate numbers but most of all it's easy because there are no decisions to make about what to eat or not eat, you just pick a meal product and that's all your decision making done!
One thing that's really important is to be sure of a plan for coming off the diet and maintaining your loss. Many people on here have yo yo'd with it many times and that's obviously not what you'll want.
If you're confident about a healthy exit plan then I recommend Exante.
The best thing about it is the speed of your weight loss (only if you stick to it 100% of course). Seeing the weight go quickly encourages you to keep going. Also it means that you only have to be on the weight loss part of your diet for a minimal amount of time before moving into maintenance.
Low carb diets can make some people feel rubbish, everyone's body responds slightly differently. Drinking plenty alongside the diet is a must to help you feel ok.
I tried Cambridge diet (similar to exante) years ago and felt terrible on it but I've felt amazingly fine on Exante. I don't know whether that is because it's a different product or because my body and health was at a different state when starting the diet.
Whatever you decide, most of the above is good to bear in mind.
Good luck! X