Under Vietnam Law, foreign enterprise can setup a branch office for conducting business activities in Vietnam.
However, in practice, possibility for setting up a branch office of a foreign trading company in Vietnam is very low.
Generally, upon submission of application dossier for setting up branch office in Vietnam, the competent authority shall direct the applicant to setup a subsidiary company as an alternative option.
Thus, if you compare between R.O and Branch Office, we recommend you to setup R.O due to the reality of this option.
However, if you do wish to directly involve with trading activities in Vietnam, you should consider setting up a subsidiary company in Vietnam as R.O must not directly conduct business activities.
Procedure for setting up such subsidiary company shall take you more time and expense in comparison with setting up a R.O (it may take you about 02 months to complete and it also require you to inject capital into the subsidiary company).