I think I should add comments about some of Paizo's standalone APs to hogarth's comments about Dungeon APs. My comments are once again more concerned with the plots:
Rise of the Runelords
Good:
- Nicely tied together. Practically every group of baddies is connected to the main plot in some way, and their action feel relevant. Connections between adventures aren't too strained, mostly. Except for the one between second and third adventures, IMO.
- Feels fairly epic, although minor plot modification to showcase later enemies' threat level still won't hurt.
- Enemies are diverse, but not diverse enough to completely invalidate preparations against certain types (undead, giants and magical beasts are quite prominent).
- NPCs are fairly decent.
Bad:
- Spikes of difficulty. The Shadow Clock tower at the end of the second adventure is particularly infamous, because you get there right after fighting various weak-ass opponents (like rogue 1/cleric 1 mooks for an entire subsection - against a 5th level party), and then you are supposed to fight an intelligent flesh golem, which has a decent chance of surprising the party, a bunch of elite mook monsters (that can spring a dangerous trap), and a flying spellcaster, who has AC near 30, 142 HPs, +11 Fort, +16 Will, Charm Monster, Suggestion and +7 ability modifier to DCs. All in quick succession.
- Villains get all the way through nausea-invoking and circle back to laughably evil.
- It is not clear why anyone who is not directly mind-controlled even tries to pull BBEG from his grave. He's your usual megalomaniacal evil overlord, and being his slave forever is not an enticing job offer. During my RotR run I decided that he still has the ability to telepathically contact descendants of the races he created and make them explode with a thought, if they displease him.
- Rubber band NPC levels.
- No way to advance the plot or resolve any of the significant conflicts, save for stabbing faces.
Ugly:
- Even if you like the idea of sin magic (I do), you probably won't like its implementation. The best attitude towards it seems to be lack of care.
Curse of the Crimson Throne
Good:
- Cool urban setting.
- There is, for once, a passable explanation of why BBEG does not destroy party and, indeed, all opposition, when PCs still are level 3 (she powers up alongside with them and isn't particularly powerful at the beginning).
- Great variety of subplots.
Bad:
- You take two-adventure detour from the cool urban setting, to go on a random-ass fetch quest in the second half of the AP. There seriously are better ways to prepare for overthrowing a nascent tyrant, than to hunt for magical weapons, because authors were too scared of making the AP less dungeon-crawly.
- Strong assumption that PCs will follow the railroad even when it is not really making sense. By the time of the above-mentioned fetch quest PCs are level 10. AFAIK, there aren't any contingencies or scrips in case they just decide to try assassinating the BBEG right now.
- Rubber band NPC levels.
Second Darkness
Good:
- The first two intallments are decent standalone adventures.
Bad:
- The difficulty is set to "Easy" from the beginning. Most of your opponents are humanoid NPCs, and most of them are shafted further by racial EL.
- The first two adventures are really disconnected from the rest. Just as PCs establish themselves in their home city and prepare to enjoy the spoils of their treasure hunting, a world-saving quests falls on them with little foreshadowing and they are requred to abandon the above-mentioned city forever.
- The plot requires from you to suck a lot of NPC cocks. And most of these NPCs are really evil.
- The plot requires from you to make at least one decision that, by any reasonable assessment, is suicidal. If PCs refuse, they are punished by thinly-veiled grudge monsters.
- The plot overuses McGuffin magic.
- It is not clear, why no one cares about BBEG's attempt to
blow up the whole goddamn continent.
- Rubber band NPC levels (see the theme now?).
Ugly:
- The drow. No, seriously, they are drawn ugly. As the whole point of the drow race is being evil and beautiful dominatrixes, this is a very major flaw
. For that matter, normal Golarion elves tend to be butt-ugly too, but at least they have more healthy skin tone.