I've got a quick question for someone with more change in their pocket than I, and have purchased both Disciples of the Dark Gods and Tattered Fates:

I suppose I'm asking for something of a spoiler here; I am tempted to purchase Tattered Fates, but before doing so I'd like to know how (if at all) it ties in with The House of Dust and Ash from Disciples of the Dark Gods. Both obviously deal with the Haarlock line, and those cryptic words I've seen about "the 13th hour" also suggests the world Solomon in common, but that's about as far as I have gathered thus far. Do Fates and Ash fit together nicely? How so? Thanks for the help.

There is a thread on this topic.

IMHO the two adventures are too similar. The themes are similar, and also the plot - see that other thread, which may contain spoilers.

But then again, you don't want to miss out on Tattered Fates. My plan is to wait until the entire Tattered Fates trilogy is out, and then run it as a minicampaign for a new group. With my current group I will play House of Dust and Ash. And the players will notice the similarities, I suppose, but I don't think they will mind.