Working Saturdays for a long time for a local hobby shop it has become clear to me a couple of things. The majority of issues with Lionel products is in top of the range items. The vast majority of people buy train sets and lionchief engines and happily set up small layouts, run them on the floor, or around the tree. For a brand new line of products, I am astounded by how few issues the Lionchief trains have had.
Remember that we as high-end 3RS operators are the very, very small minority of the O gauge hobby, let alone the model train hobby as a whole. The fact that Lionel even bothers to make high-end "scale" equipment when they could just make profit selling the mass market toy stuff is a plus for us.
Still, the issues with these new high-dollar items is inexcusable. My HO scale friends can buy a scale sound and DCC equipped steam engine from Broadway Limited or Athearn for $300-$400 and expect near-100% prototypical accuracy and no QC issues at all, save for a grab iron or two falling off during shipment. Meanwhile, my GS-4 MSRP'd at $1,700 and has some prototypical errors. I keep wondering, why in the world do I stick with this stuff? I guess I just like big, hefty O-gauge trains lol...
As for the Daylight...I have loved my GS-4 so far. With the exception of the cab roof hatch on backwards (which was easily flipped around), it has been everything I would have hoped it would be. Although, I do kind of wonder what I'm getting for $1,700 that an HO scale guy isn't getting for $400. My cars also have the nameplate peeling away on about half of the cars, and a sticky coupler or two. But they are a beautiful set and the faces of everyone who sees them on my layout makes it all worth it to me. I really care less about the "inaccurate" whistle on the GS-4 or the corrugated roofs on the cars. I love the sound of the whistle and the cars look great. If I was worried about things like that, I wouldn't be playing with tinplate couplers and three over-sized rails. But the QC really needs to up their game by about 500 times to merit the prices of these things.
My verdict: If you are interested in getting true prototypical accuracy, go do HO or N. They've mastered the art far better than we could ever dream of doing in O, and they cost a ton less and tend to be more reliable. If you just want to have fun and reliable trains, buy the lower-to-mid range toy-like stuff. It's fun and less expensive. If you want to keep on keeping on with the high-end O gauge "can't choose between toy-like and prototypical" like I am (for the time being), well, happy railroading to you...
...but seriously, Lionel needs to fix both their customer service and QC.