Yup! I do! The water serves as a temperature control and does not add to the moisture of meat in the smoker; any type of meat. If you get your jerky too hot it will quickly become inedible! And, honestly, I have not tried it without water. Maybe someone has and has had good results. I will be following the other answers as well!
When making jerky we (my boys & I) use very lean meat so you don't have any fat dripping into the waterpan that could cause a flare-up. We don't use any water in the pan because we're not generating a lot of heat. We only use 4 to 5 charcoal briquettes at a time, just enough to place the smoke wood on top of. That way we get a light amount of smoke with the least amount of heat. Afterall you're only trying to dry jerky, not cook it.
I don't think that water in the pan really adds any moisture to the meat so using water or not shouldn't influence the final product (as far as I know), but then we've never used water.
Looks like I might try waterless the next time I use my ECB. I have GOSM on the way and it will be interesting to open up a whole new round of experimentation! This could be fun!
My first try with my NEW Brinkmann All In One (converted to nat gas) was terrible. I now know why I got a $180 smoker for $89.99. The temp gage is way off, the holes for the holding brackets are hap hazard ( not level or square) and the lid has a poor fit. I have had one before that became damaged, and it was great, and I converted it to natural gas. The concept of this product is good, however their customer service is non existent. I tried for 3 wks to call in, I even tried the local number on my nickel. E-mail is answered but its generic at best.
Sorry for the rant