I know a few people on this site have used various kinds of slimming tablets, but I'm generally pretty wary. The only way to lose weight and keep it off is to make a complete lifestyle change, and make the switch to healthy, sensible eating patterns and regular exercise. Tablets may help you lose weight faster, but once you come off the tablets there is often a rebound effect where your appetite increases, and you gain the weight. Also, if you haven't properly learned the habits of the lifestyle change (eating well and exercising regularly), you won't be able to maintain your weight loss.
That's just my 2 cents. Used sensibly - as an adjunct to a healthy eating plan and regular exercise regime, tablets can help some people to lose weight, particularly those who have slower metabolisms and tend to have trouble losing weight. However, people should be very careful that they aren't relying solely on the tablets, and when they decide to come off the tablets they should withdraw them slowly - cut the dose down to half (ie one a day from two a day) for a week, and then by half again, until you are down to one tablet every two days, and then one tablet twice a week for one week, then stop. This will limit the risk of the effects of withdrawal.
Whatever you decide, best of luck. Remember, you can always discuss these things with your family doctor. For the obese among us, there are some medications that doctors can prescribe that will help shift the kilos quicker, and they can help you monitor your progress and combine it with a healthy lifestyle.