Here is my honest review of this battery in comparison to the stock battery that comes with my OMP M2 3D helicopter.
This battery offers a slightly higher C rating than the stock battery which maybe helpful for a slightly more aggressive 3D flight. In my hover testing, the runtime is about the same as the stock battery. The advertised capacity is attainable. I tried to cycle the battery on my lipo balance charger and got 605-620mah consistently. My experience with some cheaper batteries you loose at least 20% of the advertised capacity due to heat and internal resistance etc. so its good that this is NOT the case here.
The battery fits the Heli snuggly with a piece of dual lock keeping it in place. You may decide to use a velcro tie around the receiver for extra security. I did not notice any change to the balance of the heli. The weight is same as stock battery. This will not fit with the sliding battery plate.
This is a good option to consider if you are looking for batteries for this heli. I will purchase more of these in the future.