I've had a Timberline 1300 since it launched. In terms of build quality, it's great. Very heavy duty stainless grates. The dual wall cooking chamber is decent. Good seals on the doors and overall it it's a nice looking smoker.
What I hate about it is the controller. They've released a D2 version, but I have never used it. When I asked if I could buy the parts to upgrade, they said no. I had numerous sooting issues with the original version and still do. I also have issues with it heating is very slowly, so you need to plan ahead if you need to get things smoking in a timely manner. They updated the firmware, making it worse and better, but never resolving the sooting issues or the slow warmup. Using the super smoke feature always produces black soot because the run the fan too slowly, thus allowing the fire to burn uncleanly. The app has always been pretty good and I've never had any connectivity issues. I've had to remove hard parts from the cooker to make it perform better based on their support, something I've never had to do with any other brand I've owned and I've owned a lot of them.
It was and still is frustrating to me that they had a cooker which runs very even in not only temperature stability, but the evenness of the temperature within the cooking chamber. They just failed with the controller and its programming. I will never buy another Traeger product after the crappy service I received from them. Once my SmokeFire EX6 is up and running, I'm going to sell the Timberline. The D2 version may be a lot better, but they sure burned us early adopters and we're now abandoned from any updates to the firmware. Lastly the smoke flavor is pretty mild even for a pellet cooker, even when using Lumberjack 100% Hickory.