My last review of cheap Chinese propellers, Gemfan 5x3 3 leaf, was quite negative. This time it will be much, much better: DAL 5040 (5x4") fiberglass reinforced propellers. They are cheap, only slightly more expensive than super popular Gemfans 5030. But they beat Gemfans in every aspect. Not only DAL 5040 give more power and pitch speed. They are also much more durable. The internet calls them "indestructible". No, they are not indestructible, but they are strong enough to survive crashes big enough to break Gemfans 5030.
So, even if they are slightly more expensive, they last longer and give more power. It is also interesting how they break. It is either in the hub and whole leaf is gone, or they fracture is the middle of a leaf.
Bottom line: I like these propellers very much, they are surely worth the price!