We actually found people who paid us to be much more helpful and understanding with potential issues. Probably because they knew we were working hard on solving

We actually found people who paid us to be much more helpful and understanding with potential issues. Probably because they knew we were working hard on solving a problem that they paid for. We also offered a money-back guarantee, but barely anyone ask for one (<1%). Customer service isn't bad since the volume for a paid beta isn't what you'd see for a free beta. This has the side affect of keeping your beta group contained so that you really get to know your users. Free users were the opposite. They would be angry when things didn't work out quite right and complain about the beta price (roughly $5, though we moved it around some). Free also has more issues on the customer service side simply because you have to do more of it. I can certainly think of scenarios where a free beta makes sense, but if I'm starting another B2B company I would charge from day one all over again.