The Standard version lacks some of the clarity and sharpness of the Premium, which you can see in these images. The Premium has a slightly more yellowed look as opposed to the Standard's more grey texture.
The only concern is that the spine text rolled to the front cover on both versions. It turns out that Lightning Source (the printer) has a 1/8" variation margin, meaning that text can move up to that distance on a finished product and they consider it acceptable. However, I don't. After some discussion with OBS support, I've decided to remove the spine text. I'll be ordering the final proof ASAP! Sorry for the delay!
A few more images of the interior, both from the Premium version ...