There are multiple differences, as the Residential Landlord-Tenant Act provides a few more protections for residential tenants. Commercial landlords can rely on RCW 59.12 et. al. for their unlawful detainer procedure. One of the main differences is the notice required for given situations before a tenancy can be terminated and unlawful detainer proceedings begun. All in all, the non-residential unlawful detainer system is a bit more landlord friendly. If you have specific questions about the differences, please feel free to add to your question.
*This answer is not intended as legal advice but merely general legal information. This answer is not intended to create an attorney-client relationship, and no such relationship has been formed as a result of this communication.
I agree with Mr. Diener. A big plus in the commercial property procedure is that the statute states that "if the alleged unlawful detainer be after default in the payment of rent, [the court shall] find the amount of any rent due, and the judgment shall be rendered against the defendant guilty of the . . . unlawful detainer for twice the amount of damages thus assessed and of the rent, if any, found due."