After Myst and Riven were so good, I went into this suspecting that the series would start to dip in the third installment. Starting from there, the game was a roller coaster for me, because those expectations were turned on their head with a very strong introduction with excellent music and a uniqueness of setting that I didn't think they could pull off a third time. It was a "whoa - they've done it again!" moment, which was even more impressive because I had already thought that Riven wouldn't be able to live up to Myst either (which it did!).
The starting age and the first age I went to were excellent - some of my favorites of the series so far. Puzzles that were too challenging to just walk through, but not so difficult that I wanted to walk away; otherworldly setting supported by dream-like visual art and music that carries you away; a free-look system which I thought would make it feel less like a Myst game but which actually melded seamlessly into my experience; - I was blown away.
Unfortunately, the next two ages were less enjoyable. In one I just sort of stumbled through the puzzles by interacting with everything I could as I walked by, without understanding the solutions. The aesthetic and dependence on other livings beings made it seem inconsistent with the rest of the ages in the games. In the other age, the puzzles were a more reasonable difficulty, but still simple enough to make solving them feel more inevitable and less like an accomplishment. It also felt too barren.
The game wrapped up well enough - finishing higher than its lowest point, but still below its strong start.
I would recommend this if you like the lore of Myst, want to revisit the setting, and don't mind easier puzzles than you might be used to. Just maintain moderate expectations, please. It has big shoes to fill.
If you enjoyed Myst and Riven, but feel that they wrapped up the story nicely (or if you prefer more challenging puzzles), this one might not be for you.