Compared to the rest of the Greater Portland market, the Tualatin submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 10 listings have been posted online, which means new availabilities most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 140% of the available leases in the Tualatin are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,150 sqft. Most buildings in this region were built in 1998 and are Class A.