I like pellet type smoke. I guess I am accustomed to the dust it generates.
I've never cared for liquid smoke. I don't like the idea of breathing the vapors or having them deposited on everything throughout the house.
Plus, as far as I know, there are no issues with partially used SP pellets. They just re-solidify, and will be consumed next time. They never go bad. The smoke units aren't damaged by being run dry.
The main issues with pellet smoke units are overfilling, and foreign objects being put in the stack, breaking the element.
On rare occasion, they do burn out.