From my perspective, these are grills with some nice high points and a few very low points. The first generation is such a classic Weber in build quality and style - except that the firebox has porcelain coated steel fronts and backs notorious for rusting through leading to a potentially dangerous situation in use. As Larry says, when it comes to finding many parts, dream on.
The second generation was a step down, except that it brought the rear infrared burner option that increased its capability to now do rotisserie well. The bright spot in this generation is the grill you are looking at. That stainless frame is the real deal as is the cabinetry. Unfortunately, this grill also has the same firebox issue as the previous Summit. Why in the world Weber didn’t go to an all aluminum firebox is pretty much beyond me. I am not sure you can’t at least find some parts for these still, but it is true they are on the road to being orphaned. I would like to take on one of those someday. If you are willing to spend time and money you could have a really nice grill. If you are looking for a flip opportunity, I would look elsewhere.
The current Summits are to me way too heavy, complicated, and made of far too much cheap painted steel for a + $2,000 grill. I think they probably cook awesomely when in good condition, but if any grill deserves Larry’s moniker of “rust bucket” this would be the one.