From Jason Lemkin:
As a rule, the less the customer pays, the more feedback they provide, and the less engaged they are (making their feedback worse). The best feedback — and least noisy feedback — is from your most engaged (and generally most profitable customers). The biggest risk of all is listening to all the wants/wishes/complaints from the free and low-value converts and ‘potential’ converts. From that perspective, freemium can in many cases be not only dangerous, but fatal in the early days.