We lost a sale recently in a situation where a business support / marketing group recommended against us. That same group asked us for a percentage of the value of each sale they recommend us for. We refused unless they agreed to tell their members about the payment for the recommendation. They have recommended against us ever since.
Transparency matters to us, as does the fit of our POS software for a business.
If anyone recommends POS software to your business, ask them if they will receive a commission or some other benefit from the recommendation.