Brining the bird before the smoke makes it even better!!!
I used to brine the birds first in a cooler overnight but I got lazy a couple of years ago and just smoked the thawed out turkey with pretty much the same results. About the only difference is the brined turkey was a bit saltier so if one brines then it’s best to leave any salt out of the rub mix.
I think it’s the slow cooking that really makes the big difference. I find it’s best to not even check on it for at least 3 hours; maybe even a bit more depending on the number of birds. Of course it all depends on the kind of smoker one uses as well. With the electric ones; the more times the door is opened and much of the heat escapes; the longer it will take to cook. That’s why 3 to 3.5 hours is a good time to check for the one I use.
I also find using just two cups of water soaked wood chips to be enough. Too much smoke flavor can overpower the flavor of the bird. Just my humble opinion. Everyone has their own way with their own equipment. I shoot for a temp of 235 then use a thermometer to check the inner meat temp has reached 165 degrees.
I use a lot of Adobo as part of my seasoning which already has salt. If I brine plus using Adobo it might be too salty. Oh, and we like Adobo so I can't cut that out.