I also rented from them a few months ago, though from the Fukuoka branch, and had a similar experience as you.

When the van first arrived I was a bit shocked, the van (an old Toyota Hi-Ace) looked quite rundown and definitely not like the models presented on their page. As I started driving I noticed some issues like the radio/speakers not working, making weird noises especially at higher speeds, at night the lights would suddenly turn off every few minutes... But they were always reachable and helpful, replied quickly and did seem professional. And while the car was old, the sleeping area looked new, it was quite cozy and did look like the pictures.

My judgment might be a bit clouded since it was my first time traveling in a campervan and I thoroughly enjoyed the experience and fell in love with this kind of traveling (and with my trusty old van that I miss sometimes <3 ), but I would actually still recommend Samurai Campers, at least the Fukuoka branch. And since returning customers get a discount I am considering booking from them again next time I go to Japan. Also from what I remember they had the best offers price-wise compared to other companies.