In the later model MES' they reduced the size of the chip burning pan and also put a piece of sheet metal between it and the burner. This coupled with the larger heating element they also changed to caused them to not produce smoke well at lower heat settings due to the burner not being on long enough. Those who complained of "lack of smoke" issues were given the old style larger chip pan without the metal between the pan and the burner. This actually made mine burn the chips up too fast. I had better results by modifying the small chip pan by boring some 3/4 or so inch holes in the sheet metal between the chip pan and burner. All of this ceased to be of any importance to me once I got an AMNPS. I might use chips on a very short smoke or if my pellets burn up before I'm done smoking, but mostly I will just use the AMNPS. You can get TBS for as long as you need it without any work, just check on things once in a while and relax.
The window is easy to clean and I love to watch things smoking away inside. It's neat how the smoke swirls around in there.
I haven't used water in the pan since getting the AMNPS. I had some problems at first keeping it lit so I eliminated the water to see it that was my problem. It turned out to be that I just wasn't getting it lit well enough to start with. Once it has a really good red-hot spot going it did fine.
It didn't seem to make a difference in the food so I quit using water and now I use sand in the pan for heat ballast. With water in the pan you could often see drops condensing and dripping down the glass.
As for wet chips, with the oem chip pan it made the lack of smoke worse because they wouldn't burn until they dried out. After the retro-fit kit
they would catch so fast it made very little difference. With the retro chip pan I used just a few chips to smoke right away and a couple of
fair sized chunks to last a while. I would have to tend it about every 30 to 45 minutes. With the AMNPS it smokes until the pellets are gone.
I get about 3 hours to the row depending on where in the smoker I place it. Hotter spots and it burns faster.
These are the results I have had with my MES40. I'm still experimenting every time I smoke. I hope this helps.