I have also been involved in forums, also working my butt off for 'free' 'cause we feel good helping others. You can say that of just about everyone else on this forum.

BUT, never does it excuse someone who actively promotes Product X to go on a forum for Product Y and bash that product. That just is not done, ever.

The fact you get no compensation is irrelevant, as a beta tester you still represent the firm to a degree; not in a legal sense, but in a business sense.

Robert