I had no idea that there was any extended release versions of Lamictal. I take generic once a day and it has been doing me a lot of good. I get it for $10 a month, what a steal!
If you feel as though the effects from lamotrigine fade off from once a day dosing, you can split pills or just ask to be prescribed smaller doses to be taken at different times of the day.
Extended release versions of meds are just a way to extend the patent for the original drug manufacturer. Generic works just fine.