Same as the MBA.
My guess is that the Retina display will always be glossy only, but I hope not. Just as we'll probably never see a matte iPad.
If you get a chance, have a look at one in person. It is glossy, but significantly less so than previous models. It's built differently, and has fewer layers of glass.
I find the article Amin quotes kind of funny in its premise. The writer comments on the lengths Apple will go to in order to prevent tinkering. Yet for any of the current MacBooks, it takes only a few moments to swop drives or add RAM. Just look at what Kyteflyer is considering.
The writer should watch the keynote introducing the Retina MBP. In order to achieve its size and weight goals, they had to start from scratch and re-engineer. The writer implies that using proprietary parts is a bad thing - but without doing so the machine could not exist. It's an example of Apple pushing boundaries. For some people, not being able to open, fiddle or change things is important, and so this machine is not for them. But most buy one for 3 - 4 years of use and then upgrade, so it's fine. Apple didn't close it to keep people out, but in order to make it possible.