I realize we are all resolution junkies here but I seriously doubt anyone could pick out a 1856 frame upscaled to HD vs a 1880 frame upscaled to HD. It is less the 2% difference in resolution. I bet if someone posted 10 shots with 9 1856 and 1 that was 1880 scaled to HD you wouldn't be able to pick out the 1880. Pixel peeping at %200 percent is virtually unnoticeable even when toggling back and forth, I can only see the slightest difference it very high contrast areas. Everywhere else shows no change and I certainly cannot say that one looks better than the other. I had to constantly remind myself which on was which when I was trying to determine if one was better. I have 20/15 vision BTW.
The difference in quality is so tiny it really isn't even worth the extra effort, I don't think it should even be called a quality difference just a difference. I would recommend shooting 1856 to get longer record times and smaller file sizes - 1856 is continuous and 1888 is not after all. I know there will be the "I want the highest resolution and best quality possible even if it is 1 pixel" replies, but in reality the quality difference is only in your head. If you disagree show us an example of how much better it is, if you can.