Excellent bad guys but multiple authors are a little uneven with the Vong. Example the initial authors made the Vong vicious and xenocidal exterminating large populations, but about midway through the books when a highly populated planet fell I assumed the vast majority of it's population was exterminated. The next book a different author saves the population by making them refugees that were expelled by the Vong (Completely inconsistent with earlier writers).
However, decent read with different approach Tech versus Bio Tech (Vongs weapons, ships etc are living organisms and the Vong hate mechanical technology).