Just wanted to chime in and say that Slumbering Tsar has been some of the most fun I've ever had running a campaign--and getting a rousing endorsement from Steel Wind is particularly keen and somewhat serendipitous in particular from my personal standpoint because I ran the Price of Immortality trilogy to get our party up to 7th level so that they could segue into Tsar--and listened extensively to his podcast when re-tooling and making adjustments to those modules.
We're running with a quite large party with players that are very mixed in experience (from some who have gamed since first edition to those for whom 3.5 was their first, and one who has played through the entirety of Rappan Athuk--and their Tsar character is their successor!) and we've been going for 22 weeks of 10+ hour sessions and we're just -barely- into the fourth and fifth book of the originally separate fourteen.
The amount of content is mind-blowing, frankly; there's so much to explore and encounter in the Slumbering Tsar Saga that a group can absolutely get a ton of bang for their buck out of it. I think the biggest factor in this is the sheer variety of the environments and encounters; all too often, material that even begins to approach this magnitude has a tendency to begin forming gluts and ruts of similar situations--but even in a party's first forays into the Desolation you're dealing with everything from a half-blue dragon greater basilisk with a mad derro sorcerer companion to an Army of Darkness style battle royal with waves of undead.
Greg has really done a terrific job with Tsar and I am so glad that something of this size and magnitude made it through the journey that it did to be available for folks to play; the story behind the whole of the work is epic in and of itself. Even if you don't foresee being able to run the Saga in its whole form, there's so many things that could certainly be lifted whole cloth and added to other adventures (such as the mentioned Army of Darkness fight, which was really a ton of fun at the table, or the entirety of the Crooked Tower, which is a roughly 80 room dungeon home for a powerful vampire lord.)
So overall, I highly recommend the Slumbering Tsar Saga as well and am also eagerly looking forward to the fruits of the Rappan Athuk rebirth--and definitely encourage folks to bip over to the kickstarter and help show that there is still a desire for such detailed, devious and deadly dungeons. If you're interested in the Tsar Saga at play, I've been blogging with session recaps, player journals, photos from the table and other such things over at
Stranger Sojourns as well; Greg's labor of love has been a lot of fun for both sides of the screen!