Just got my Superliners as well as a few Viewliners and one Amfleet in today. Absolutely gorgeous cars, I love the Sightseer Lounge car. I had one duplicate road number sleeper, but otherwise seems like a flawless set.
Just got the rest of the cars unboxed, I'll post more photos and videos in a minute but wanted to go ahead and give some more detailed thoughts on the cars. Overall I'm incredibly pleased with how they turned out.
Superliners: The trucks on these cars are very well done. Being Superliner I cars, they have a unique design which has only been done previously in O Scale by Overland brass. The trucks have many separately applied parts which captures the look of the prototype nicely. I wish the bearing caps rotated, but otherwise great trucks, which roll freely as well. There is no underbody detail but that is to be expected and would be pointless on cars that sit as low as these do. The paint and finish is very nice and captures the look of stainless steel. The striping, logos, and lettering are pretty good with only minor imperfections. There are separately applied grab irons, handrails, and stirrup steps. The windows sit flush with the car and have simulated rubber gaskets which look nice. I would've preferred if the windows were slightly tinted to match the prototype however. The interiors are pretty good. The layouts are all prototypical for each car, but I will be repainting all the interior walls and adding details/ more modern figures. While I'm not the biggest fan of GGD's "little people" figures, these cars do have more figures than any other cars I've bought from them over the years with some cars having as many as 15 people in them. The seats in the lounge and coaches are well detailed and correctly oriented, but do not match the shape of the real ones. The LED lighting is an appropriately warm hue and the cars have capacitors for flicker free operation. Lighting in the sleepers isn't as even as other cars due to the walls for the rooms, however this is honestly probably more realistic as not all rooms would have the lights on. Each car has red marker lights on both ends which can be turned on or off by a switch on the bottom of the car. Unfortunately, if you turn them on it does both ends of the car rather than being able to choose one end.
Amfleet: I only bought one Amfleet (hopefully they'll do Amfleet IIs soon). All comments about paint and lighting from the Superliners carry over. The trucks roll much stiffer but that's not surprising given that they are inside bearings. I ordered a café car but it has a coach interior so I'm not sure if that was a factory mistake or an error on GGD's part.
Viewliners: I got 3 from the first run a couple years ago and 3 more this time. The paint is a spot on match between both runs. The dining car interior layout is correct but there are unnecessary partitions in the dining section of the car and then an odd table where the kitchen wall should be (this car is from the first run, not sure if they updated that in the second). The baggage dorm car (really cool in real life and model form) has luggage racks in the bag section which the full baggage doesn't (also possibly due to different production runs). One thing that really impressed me with the sleepers is that the Phase III cars have tan interior walls and maroon beds/ seats while the Phase VI cars have white walls and blue beds/ seats which is prototypical as the real cars have different interior finishes, great attention to detail GGD! I do wish they had taken the time to model the Viewliner I underbody for the Phase VI cars instead of the Viewliner II enclosed underbody, but not a deal breaker. These cars roll well like the Superliners.
All in all I'm super happy with all these cars. Most of the critiques I had were me being super nitpicky just because I ride Amtrak so much. It's great to finally have a scale modern Amtrak train. @sdmann you and your team should be very proud of these cars. I eagerly await the P42s and Chargers I have ordered to pull them, and please please please make Amfleet II coaches so I can complete my single level train.