I played this one a few days ago, and while it's a decent scenario it's not one of my favorites. The main problem I have is that based on the initial description you can wind up picking a character who doesn't have much to do, mainly because it can be much lighter on combat than you might expect.
That said, it's nice to see a short scenario like this one sometimes, especially at a higher tier. That probably makes this a good one to use for conventions where you have to keep to a tight schedule.
True Dragons is worth playing just for the large encounter in the middle section, but the rest of it is pretty good too. If you get a chance to try this one, I strongly recommend it. The only real caveat is that you need to keep an eye on the time a bit, because it is a scenario that can get away from you depending on how long the PCs decide to take on some things.
Through Maelstrom Rift is an interesting adventure that everyone involved in Season 8 should have a chance to play, which is why it's a shame that Paizo has made it one of their restricted adventures. It has a good mix of somewhat-unique challenges, though that occur in a bit of a strange order that left me wondering whether I needed to save some of my abilities in what might or might not have been the final fight.
I've both played and run Web of Corruption, and though I had fun both times I don't think it's a terribly well-written scenario. There were at least a couple of times during the investigation that I simply had to say to the players, "yeah, I'm pretty sure that's a plot hole you've just uncovered".
For one thing, the Spider depicted here is hardly the criminal mastermind she's built up to be. Her notes clearly reveal her identity for no discernable reason, and her tactics in the final encounter are downright stupid given that she could just run for it, especially if you have six PCs instead of four.
There are other questions too. Why is the Sailswift still in the harbor now that the slaves have been delivered? It's clearly stated that there's only one shipment a month. By the same token, why does Jarovar wander around every night when he usually has no deliveries to make?
Basically, this is another fun-with-the-right-group scenario - there's a good mix of stuff to do here as long as your group can get into it and overlook of the details. But there are many other scenarios that offer the same thing without these drawbacks.
From a player's perspective, The Midnight Mirror has a strong plot with good pacing, but is let down somewhat by poorly-tuned combat encounters. Groups with the right composition will find the combat nicely engaging and challenging, but others may find it downright murderous. For example, rogues will be annoyed to find several enemies that are immune to flanking. Our GM wound up fudging several rolls so as not to kill people too early. There's potentially a lot of fun to be had here, but I'd make sure that players understand what they're getting into.