Seattle's streetcar network is controlled by the city of Seattle instead of county or regional agencies that bleed money due to the suburbs. They're much cleaner and more reliable than buses. The SLUT is worthless for most people because it doesn't go anywhere, but it's a pleasure to ride if you use it. The BUTT will actually be useful and will be built next year.
Blame Nick Licata for the other three lines not going forward. Vote McGinn, O'Brien, Bagshaw, and Israel if you want an in-city alternative to buses.
BUTT - ID, First Hill, Capitol Hill
FABQueen - CD, ID, downtown, Belltown, Queen Anne
SLUT B - Downtown, SLU, Westlake, Ballard
SLUT U - Downtown, SLU, Eastlake, UWMC, U District