i dont' like them for several reasons.
first of all, the side effects aren't great. they can include minor stuff like jitters to major stuff like heart damage and death depending on what you're using, your
physical condition, your genetic profile, and other substances you're exposed to (smoking, coffee, heavy fumes from traffic, etc).
secondly, they dont' address the underlying problem that caused the overweight in the first place. so you take them, lose the fat, and stop taking them. what happens next? your eating habits probably haven't changed so you'll start
gaining weight again and you'll have to take the pills again.
thirdly, most of them feature caffeine, which is highly addictive and adaptive - over time, your body adjusts to it and needs ever-increasing doses to get the same effect.
fourthly, you might lose weigth too quickly - this means you're losing muscle mass and lowering your metabolism, which means you'll gain all the weight you lost PLUS extra when you stop taking the pills.
your best bet is to track your caloric intake over a week and see exactly what and when you're eating, then modify it as needed. you'll need a small deficit of 500cal/day to drop a safe pound a week - drop your daily intake by 250 cal and increase your activity 250cal for three weeks. if nothing's happening, drop another 100 cal (50/50) for three weeks - repeat until weight starts to drop.
your body is for life: surely it's worth a few months' effort to undo the damage that's been done over the past however long? there are no magic bullets, pills, lotions, potions, or creams - only hard work and commitment.