Seattle seems like it's doing well with Ofo, Limebike, and Spin however it will never be a replacement for a car, and they're 40-70lb bikes that can't make it up Seattle's hills which makes them kind of useless outside of downtown. They are used often and I see people riding them all day down by the waterfront, especially in the late spring/summer.

I unfortunately don't see them being any kind of major replacement for anything in Seattle anytime soon unless the Mayor actually puts high tolls on downtown exits -- especially since we have fairly good public transit.