After reading this opening post, being TOTALLY at a loss, I did a bit of research. I now know what a WSM 1880 is (a smaller smoker than the 18.5). I admit that the 1880 is a cute little smoker and probably works quite well. Historically, I found it quite interesting.
However, after going back and forth trying to decide on which model to buy, myself, I got the 18.5". I am VERY happy with my choice. I am not sorry I didn't have a chance to buy an 1880.
FWIW
Dale53