For testimonials it would be best to go straight to Trip Advisor and Google Business. The latter I only set up properly recently, so for now there is less activity.
Speaking of less activity, in March 2020 Vietnam has closed its borders for inbound tourists, so the reviews have more or less come to a stop.
The first 203 reviews concern Hoi An Photo Walks, but since late 2018 the name has changed into Photo Voyager.
Why the new name? Check out this page!
Since doing tours in Hoi An I have received a certificate of excellence every year. It makes me happy that all my hard work results in happy people showing some appreciation. If you keep coming and post your experiences I am sure there will be another one when Vietnam is open for tourists again. This may be somewhere in 2022 or even later.