We have the big one, though not stainless. Two years old.
Positives --- Everything you have heard about. It is an unbelievably easy way to cook and smoke, no flames, piece of cake. Everybody becomes an expert. We love it.
Negatives --- Since you asked:
Paint sucks. Rusts, flakes, etc. But I see no evidence that this is a structural issue. It just looks really ugly.
Once in a while on "smoke" setting it will stop burning the pellets. The fire just goes out. That is never a problem on medium or high settings. But if you lose fire on "smoke", and you are not on top of the problem, ugly stuff happens. The auger keeps auging, and the pellets simply build up in and around the fire box. Then you come home from the massage therapist and discover the fire is out. You reset the hot start, and BIG smoke occurs. Like BIG. Maybe flames. Not cool. Never leave when smoking stuff. If the smoke stops, re-set the lighter sooner rather than later. Traeger ought to figure this one out as it can be a pain in the butt.
Cleaning is a chore. Takes about 15 minutes and can be messy. Until you get the hang of it and then it gets quicker and less messy. I clean mine every 10 uses or so. Basically you remove the aluminum foil from the hot plate and vacuum the build-up of ash. Other users reportedly clean theirs rarely or never. Take your choice. I once let it go about 20 uses and had a major flame up of the deposited gunk. Not pretty. Ruined three great burgers.
On balance, I will NEVER go back to a conventional BBQ.