Dry rubs.... Just watch a few BBQ cooking shows and competitions, all use dry rub. I can only recall seeing one contestant in a contest that wet/marinade their ribs.
Wet chips (CHIPS not Chunks). I soak the chips for approx. 30 minutes, if the electric element is on when I put the chips in, they will start smoking in less than 5 minutes. The MES allows you to add chips from outside, you can put a few chips or a more, another brand of electric smoker that requires you to open the hatch to add chips, which may be a larger quantity of chips, wet might be a problem, so dry could be appropriate.