I've been on lamotrigine for years, 100 mg per day. At this dose, it helps me to be pretty stabilisied. We tried higher doses, but that made me too numb and indifferent. At the same time, no dose (up to 400 mg) was high enough to prevent me from falling into the abyss under the wrong circumstances. At this level, it stabilises me enough without side effects that I really appreciate having it. No comparison to how some antidepressants like Fluoxetine and Paroxetine fucked me up.
But just as a reminder, different meds do different things to different people. My experience with them is in no way a guideline for anyone else.