Let's say it would depend on who you valued more. The person who asked for a straight up answer and honest opine, Or the friend you partake with charad of pretence that the said product is wonderful.
Does it really matter if it's a simple audio circuit or a trade secret. It falls on 'your' morals as the person to whom a question put forth to. if then conflict between opinion and friendship. For what side of the fence will you sit? with a friend, or with honesty.Sitting with honesty can provide a better nights sleep.