Just tried out the demo. Started as Bohemia, tried to keep Hungary in the PU but failed. Got the emperorship, but shortly afterward Hungary DOW'ed on reconquest of Ratibor, Muscovy dragged me into a war with Poland, Austria DOW'ed on subjugation, and Brandenburg eventually joined the fun with an alliance CB. Luckily Poland was going through rebel troubles at the time, but in the end I came out with just Bohemia, Erz, and Breslau. Played for a bit longer, went into a regency so I lost the emperorship, then got fed up and quit when Hungary DOW'ed a second time without a casus belli.