I don't like butts or brisket from a pellet grill in comparison to other cookers though. The smoke ring is fine, it's the texture and taste of those long cooked meats that doesn't quite cut the mustard.
Jason, knowing that you have tried about every style cooker there is, seems like the really long & slow cooks you prefer the stick burner to others due to the difference in texture.
What is different, probably hard to explain.
In MY opinion. the taste of pellet cooked food on long slow cooks isn't as good as a Kamado or stick burner or even the Smokin-It I had but as you said about texture, the MAIN thing was that the meats (butts and briskets) were not in the same league tenderness wise, they didn't render as much as other cookers. I don't know why but I think it's the way the heat moves around in a pellet cooker that is part of the issue. I think if I did the Texas crutch on them or cooked in a foil pan it would've helped but I never got around to doing that since I had other devices at my disposal, lol.
I'm am not trying to throw shade at what any body cooks on or what they like, it's all personal preference. I have spent time and money trying to find what I like, chasing the unicorn if you will. After owning MANY cookers of various types, I have found my starting line up for different cooks. Pellet grills/smokers are VERY versatile but when it comes to being a one trick pony that is designed to do ONE thing and do it well, that's where you'll find the magic. The KBQ blows the doors off of ANYTHING I have owned, cooked on or eaten food from when it comes to smoking. It can ONLY smoke but it does it superbly.
The Keg and all kamados are excellent Jack of all trades cookers, not the best smokers but good. They really shine when it comes to high heat cooks and baking, good pizza makers! Pellet grills, for me, are awesome at ribs and chicken. I grilled some chicken tonight on the Pit Boss to make paninis and they were excellent! Light smoke flavor (short high heat cook).
I can tell you this, I will never not own a pellet pooper or a KBQ. If I could only have 2 cookers (God forbid, lol) those would be the 2. I would ditch the flat top even though it's a hoot to cook on. I would ditch the Kegs (don't use them anymore at all, sad to say). I would ditch the UUNI because the Pit Boss gets to 500° and can hold a BIG pizza stone. The gasser can go bye bye as well since it's a holding oven these days, lol. The Weber would be missed due solely to the rotisserie.
Long winded as usual, but I do like to talk BBQ (don't we all?)