The traeger brand is well built. The D2 stuff now on the pro series is alot better then the older models, because they went to Dc motors for easier and more precise control. Rock solid units. They go as low as 160 and up to 400 on the 575 and the 780 models. Think the more expensive models go higher. The ironwood vents through the back which in some cases isn't good because of where it would go in someone's porch or backyard. However I've heard that it creates better smoke flavor than the other units. The 575 smokes better than the 780 for some reason. Might have somthing to do with air space within the unit and fan control. Essentially it's just a convection wood fire oven.
The GMG grill are also good so I've heard. I'm actually thinking about buying one based on its features. They don't go as low as the traeger. Think the go low to 180 or 200, but can go up to 500. The new models are 100 percent DC. Have the sight windows, interior light, and ability to control the heat damper tray which that could result in more smoke flavor imo. To me it seems like a small adjustment on the convection of the Unit. Which to me seems like a great idea. Seems the GMG grills pack more intuitive features but I don't have experience hands on to identify actual material quality. Traegers material thickness is really good for a consumer style grill.
None of these pellet grills are comparable to a 5000 dollar offset wood fire smoker, however super convenient, and cheap to run. Pellet bags are 20 bucks each. Seems like one bag of pellets is about the same as one bottle of propane.. the 575 will do a 15hour brisket using around one bag of pellets.
The weber is also a nice choice.been researching them alot lately. They might do a better job on actual smoke flavor and penetration however they are drawbacks. They don't have a drip tray over the firebox. Which led to grease fires when they first came out. They do have 2 racks though so you can put a foil pan on the first rack and drip below into the pan. Personally I don't like that it has small hazards. I like to set it and forget it.
Either way traeger or GMG are the best ones Imo. For under a grand the 575 is awsome and cant go wrong. The GMG ledge might be as good or better. That size grill seems to work the best imo.
Between me and the boys there is 3 machines. My good bud has the 575 which we use alot. My other good bud has the 780 which we can't get to smoke as good as the 575. We have the tailgater unit on the big boat which does a helluya job. No features really but hey it's a boat. The smaller machines smoke better for some reason. They all do a steller job however I'm looking into the GMG ledge currently. About to pull the trigger on it.
Edit: the new GMG ledge models etc can do 150 to 550 temp. So that's an upgrade from their previous models. Must have skipped that part when I was reading up. Bonus