The Siege Assault list looks pretty interesting. It's for use with the space marine book. It changes the force org chart so you gain an extra heavy slot at the cost of a fast attack. You also get a new warlord traits table assuming your warlord isn't a unique character which has very nice stuff on it. You can also take your, dreadnoughts, predators, whirlwinds and vindicators in squads of up to 3. So you could have 12 vindicators if you wanted. You can give your tactical squads little shields that let them re roll armour saves against shooting attacks. (no dedicated transport though.) There's an assault squad that can take a land raider as a transport. It's essentially dred mob for space marines. If you have lots of vehicles or play Iron Hands you should seriously take a look at this. Even if you don't want to take your vehicles in squadrons the extra heavy slot is worth a look. There are some drawbacks though. Namely you can't take drop pods and you have to place a special objective called the siege objective. Unless you completely table your opponent or control the siege objective you can only draw the game regardless of how many victory points you have.
The Tyrants Legion looks like it would be a ton of fun to play. Its basically based on Huron Blackheart's chapter before he became Huron Blackheart. It's a renegade Space Marine chapter. It's a combination of Imperial guard and space marine stuff. And you can make some crazy balls to the wall combos of Leman Russes, space marines, conscripts, auto turrets, lightly armored flying transports. It was intended for use to make Astral Claws/ Badab War stuff but I see no reason why you couldn't use this list to make your own renegade Space Marine chapter. If you have a bunch of random space marine and Imperial Guard, or even some Chaos stuff, just lying around, mix it up and see what you can come up with using this list. Just be aware you have to include at least 1 unit of Legion Auxillia (Essentially cultists only better). You also have to take a Tyrant’s Legion Centurion in games of 1500 points or more.
I think the real question now is can these lists be used in tournaments now that they are freely available?