I have the MES 40" 20070613 (Lowes) without window. In various tests in which I went with the thermometer fully inserted in the meat, and half inserted into the meat, the probe read about 21 degrees hotter than the actual meat temperature. I have to feed chips into it about once per hour to get a reasonable amount of smoke flavor. The A-Maze-N pellet tray will probably be my next purchase, followed by the Maverick ET-732 for accurate meat temperatures without opening the door.
Overall, the smoker has produced good meats, but as it comes from the factory, requires more effort than I originally envisioned.