I could say lammasus don't look silly, but then I'd be lion.
A lammasu has 7 magical beast RHD. They're large, with stat boosts all around (ranging from +2 to +12) and a natural flight speed. Unlike their animal lookalikes, lammasu do not have a bite attack. They do have Pounce and rake, though.
They also have various supernatural abilities. A permanent Magic Circle Against Evil is obviously positive (I like not being mind controlled), and the same goes for the limited-yet-useful Greater Invisibility and Dimension Door SLAs.
In spite of all this, the lammasus most important feature will always be its cleric casting. It starts at 7th-level, meaning a lammasu will easily be able to attain 9th-level spells. The available domains are kind of sucky, but one can't have anything.
Personally, I think lammasus deserve +2 LA. With their HD and casting they make a great base creature for a melee-focused cleric. Things every melee character needs (flight and pounce) they get for free, not to mention their impressive stat boosts. All that warrants being behind a spell level in my opinion.
...And speaking of spell levels, next up are liches! Stay tuned!