IMHO it is the weakest from a puzzle standpoint of all of the Myst games, but has a decent storyline. The big drawback is that is is too short, and the individual ages feel very small. The graphics are very pretty, but it is 3D instead of point and click pre-rendered so this requires a beefier machine. It does support widescreen resolutions tho (because of the 3D engine), something Revelation did not do.
It is the first Myst game written and developed by Cyan since Riven, and I had high expectations for it, which it did not come close to living up to. just seemed underwhelming. Throw in the $10 Mac User surcharge (Special edition Dvd, with added useless junk), and it is not worth full asking price. But still I actually enjoyed it while playing it, just felt let down upon reflecting upon the whole 'experience', but YMMV.