Price / quality very favorable.

For the price, these Yongnuo flashes (I took two) surpass many other major brands.
They have nothing to envy the most famous and more expensive devices.
Their qualities:
- The price
- Integrated radio trigger (more)
- Beautiful building (be careful maybe the battery door, but I think Yongnuo worked on the problem)
- High power (NG 56), easily dosed
- Wide control screen
- Advanced features
- Port for external battery
- Delivered with a cover

What can we blame them:
- Manual and non-TTL operation: bah, yes but we know before buying, and the manual mode "studio", that is enough!
- The biggest criticism is the lack of French-language textbook, and after much research, I have given up hope to find one on the internet ... Reading the manual in English, and good ergonomics flash were enough for me to use it quickly.

Conclusion: A VERY good flash!