I've owned mine for about 4 months now and use it all the time. Just smoked me a dry brown sugar cured bacon on Sunday and a few deer burgers.
The heated come out in two prices just later in for dishwasher cleaning. Their easy to clean, I just spray some olive oil on them as a release agent. Do you have to take them out? Well no, but why wouldn't you?
Grease can leach down, but I keep mine all wrapped in tin foil and cook indirect. Very easy clean up. Still haven't had to clean my fire box or innerds but I've gone through about 100 pounds of pellets so I plan to take it apart and see how she looks next time. I expect very little cleanup will be needed at all.
