Here on Kaua'i, the little islands in the parking lots at the mall are covered with the zoysia. It looks exactly like a very light green astroturf. It grows slowly and very tight.

The cool thing about seashore paspalum is that it is very salt tolerant. You can even irrigate it with seawater! If you get weeds or another invasive grass, just sprinkle some salt, or saltwater on the area.

Both are warm season grasses. I do not know if they will survive in Oregon.