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Yes, this is Myst, the same Myst you can find in the Masterpiece Edition also available on GOG, however, with a few additional kinks...
First off, obviously, it's in full 3D. Not quite a splendid 3D rendition, considering the age of the title, but it's still pretty well done. The atmosphere from the original Myst is kept the same, and the 3D doesn't feel like an unnecessary addon, but a part of the experience, and that's a plus in my book.
The controls can make your playthrough easier - you may freely turn, explore and find more nooks and crannies than ever before, and it's really cool if you're a Myst player from the beginning.
And, there's a completely new bonus Age to explore that connects to the following chapter, Riven, with a lovely new puzzle, too.
Other than that, it's the same old Myst like we always knew it. If you like static, but prettier images in a storybook fashion, get Myst Masterpiece. If you would prefer a more modern approach and have sleeker input, get RealMyst. You won't lose anything in either case.