I've just upgraded from an old (8+ years) traeger to a 640s. The traeger served its purpose admirably, getting near daily usage (benefit of being in SoCal), and teaching me how to smoke using a pellet machine.
The old beast started to make horrible sounds (the fan and auger were starting to make horrible sounds, the firebox was showing signs of significant heat corrosion), and I was starting to find the lack of cook space to be an issue (I bought a smallish one).
So did a lot of research and settled upon the Yoder as the replacement, went and checked out my local dealer and had a look at one set up, and came away even more impressed (nothing beats seeing one in person and feeling the weight and build quality).
I ended up waited a couple of weeks, and then went and ordered it on a Thursday afternoon around 4pm, and had it delivered that Saturday at 9am (and of course it chose that Saturday to rain most of the day). Finally got to burn it in late Saturday, and did my first cook (pork butt for pulled pork) on the Sunday.
Came out perfectly, more control and more even temps that I could ever get from the old beast.