I've used both, the Lyman was an OLD pot (cloth covered cord) and the Lee is my 20 pounder from about 10 years ago. I don't remember much about the Lyman but the Lee, I love it; mostly because the cost and its large enough I can get a good mix and don't have to cut lead into small pieces. I don't have much trouble regulating the heat, but I pay close attention to it. Never used a thermometer, just went by thrown bullets to gauge temp.
I don't have much use for a bottom pour pot.