I have a window on both my 40" Gen 1's. Until my first one, which is loaded with smoke residue fails, I'll use the second without smoke as an indoor/outdoor oven and for an extra holiday oven for people that bring dishes to heat. I am currently cleaning the window regularly after smoking. I'm trying to find out if new MES owners are more prone to baby their new toy before realizing it's an oven that never needs to be cleaned (other than the racks.) Then realizing they've been spending too much time on the transparent part of the smoker or if they really get a benefit out of looking through the window. On the Gen 1 the window isn't as big as the others so I can't see my AMNTS etc. Can you see the AMNPS in the Gen 2 and 2.5 BT with the bigger window? That would make a difference on keeping the window clean. I guess looking at the top vent for smoke is the same as seeing the AMNPS through the window if it's visible. I got my MES with a window because I found it cheaper than without. Otherwise, I would have gone windowless like my other smokers and grill.