Decent bicycle light cost

One ofthe things that I've noticed about decent bicycle lights whether internal battery, exteranl battery or dynamo is that for the average person the light is expensive. I bought my CygoLite Riover II light nearly ten years ago and I ONLY bought it becausethe bicycle shop gave me a money back guarantee if it did not meet my riding needs. Mountain Equipment Co-op (aka MEC) here in Canada also offers a moneyback guarantee if something doesn't meet the customers needs.

With a dynamo hub system that's pretty hard for a shop to do unless they offer the customer a loaner built up dynamo hub wheel. I KNOW thatthe hub dynamo light I tried otside a shop in another city about 50 kms from me did NOT match the brightness road illumination of my CygoLite Rover II light and especially at low speed.

My questions then are; #1. do you go to the expense of buying a bicycle light without having a money back guarantee if that light doesn't wrok for you the way you need it too? and #2. do any shops you use give such a guarantee if you want it and would they stand behind that gurantee?

Cheers