I have a Green Mountain Grill, Daniel Boone, a WSM and a Primo XL. In terms of smoke flavor, you can rate the WSM first, then the Primo, then the GMG. In terms of ease of use, the GMG is the easiest.
I started with a Traeger 075 and was getting wild temp swings. I really didn't like that I had to mess with the P settings to try to get closer to the temps I needed and anyways, Traeger recommended against it. I finally had enough and returned it. That's when I got the GMG...what a difference! Temp settings are precise and swings are held to 1 to 3 degrees max. The control is amazing. For the money, you cannot get a better pellet grill. Customer support is equally amazing as you have probably already read.
After a while, I thought I wanted more smoke flavor, so I added a Smoke Daddy to the GMG. That gave me all the smoke flavor that the WSM produces. Problem is, I got hooked on working with coals and wood in the Smoke Daddy and wanted to try my hand at more basic smoking, hence the WSM and Primo.
Now, if I want to be assured of a great cook or I want to do a long over nighter, I'll use the GMG. I really have to screw up to mess up a meal in it. If I want to play or experiment, I'll use the WSM or Primo. If I could only have one smoke, I think it would have to be my GMG.
No affiliation to GMG...just a totally satisfied customer.