Either would, both are suitable. Use an AVR if the main equipment are computers or computer like equipment. However, some small generators produce a wave shape may cause problems for the AVR/SVS measurement circuit. You can get very large frequency fluctuation too. Make sure the gen set is rated to at least twice the required current so as to reduce some of these problems.
The Sollatek SVS is also Genset compatible and that would be the model of choice for small generators.