Yun520 and Betty may have financial ties to Ultrax, based on their past posts.
Agree, delete the word "may". Betty is one of the internet names used when you get a PM from Tattu requesting you post battery availability.
Some comments on batteries and flight times. First off I'd like to say I don't personally know anyone that has obtained advertised flight time from any consumer system. Everyone has always obtained less than advertised. For those new to multirotor stuff I can understand if they become a bit irritated. Best guess from my side is that all manufacturers are more concerned about selling as much product as they can than they are about honesty in advertising. If there was even one test flight under extremely controlled conditions where they generated the advertised flight time they would not be lying if they used that time in their advertising. They would be very disingenuous though. Some makers may actually flat out lie. Personally, I became used to it and look at an advertised flight time and automatically cut it in half to estimate what real world flying will allow. Perhaps it's similar to the old mileage statements that were placarded in new car windows. used to be to obtain that level of mileage you had to be rolling downhill in neutral with the engine off and have a tail wind. Government has forced a change in how those numbers are obtained and they are now closer to reality but we don't have any such truth in advertising controls on multirotor manufacturers. They can pretty much say whatever they want and the only thing that can be done about it is factor it into a purchase decision.
As for the battery brands and milliamp ratings themselves there are a few things to consider. Batteries of the same chemistry, the same capacity, and very similar weights will produce similar flight times under similar flight conditions unless there is a significant difference in C rating. Bear in mind that higher C ratings progressively increase battery weight with the increase in C rating. The lower C rating generally provides more flight time as long as high discharge rates are not imposed on the system. High discharge rates can deplete a low C rating battery quickly, and could, if the demand was high enough, place more of a demand on a battery that it had ability to provide. In such a condition the system could enter a "brown out" state and fall out of the sky with a freshly charged battery. Batteries with larger amp ratings (more capacity) will generally provide more flight time, but not as much as one might anticipate if they weigh more than smaller batteries. Bear in mind that a battery only a few hundred mA larger than another battery will not produce significantly more flight time. The stock Yuneec battery is labeled as a 5400mA battery while the Ultrax is labeled as a 6300mA battery. Weights are about the same, as are the flight times you will obtain from them under similar circumstances. This has been proven many times over and we might assume that Yuneec has mislabeled the capacity of their batteries, something they admitted to doing with Chroma and Q batteries previously. So lets assume the stock and UltraX batteries are essentially the same. We might also assume the Morpilot and Powerextra 6300mA batteries are also very similar except in weight, with the Powerextra being considerably heavier that the others, which suggests it may be of a higher C rating. It's possible they may be of a higher C rating that would justify slightly higher pricing but with the exception of the Powerextra the weights suggest to the contrary. We should also consider makers want to make the most profit at the lowest production cost I doubt they are of a higher C rating. Looking at the capacities and weights we should not expect to see a significant difference in flight times, with the exception being the stock Yuneec battery. If it was truly a 5400mA battery we would expect to obtain several minutes less flight time than with the others on the list. That is not how it is though.
As for actual flight times, I've only used stock and UltraX batteries so I don't have comparative experience with the others. I do know that flight times between the stock and UltraX batteries are very similar under the same flight conditions. The times and milliamp input to re-charge using the same charger and charge rate is very close to the same between the brands and labeled capacities when they start out at the same voltage levels. This is what suggests, to me, the Yuneec battery has once again been mislabeled for reasons known only to the manufacturer. As for flight time itself, I question anyone that states they obtained 20 minutes "flight time" with either of them. If they actually obtained that amount of time my guess is a large portion of it was spent with the aircraft powered up sitting on the ground before arming the motors and they didn't do much "flying". Admittedly I fly fairly aggressively but the most flight time I've been able to obtain from either brand has been around 14 minutes. To do that I had to run the battery down to 14.3 volt, a level I don't consider "safe". Using 14.8V to 14.6V as a landing voltage the flights times range from 6 to 11 minutes depending on how the H's were being flown and the amount of wind encountered. I have since started using 14.4V as a landing voltage as numerous charge cycles with both battery brands have established the batteries have not been depleted past the 60%-70% level at 14.4V under load.
All the above brings us back to anticipated flight times. Previous experience taught me never to believe advertised flight time, while actual use of this system has established I should plan flights around a "safe" flight time estimate of ~7 minutes, under average conditions. Using the voltage monitor allows the user to obtain the most flight time from each battery, and limiting how they fly can add a little more time. Because of the higher capacity the GiFi would logically provide more flight time. How much is totally influenced by several factors, all of which are under the control of the user. Those conditions are what makes estimating "true" flight time for everyone impossible to achieve. Everyone flies differently, conditions vary widely, how the camera is used impacts battery life, lights on or off, GPS on or off, etc. Those are reasons we might use a very conservative time value in our flight planning, while using displayed battery voltage instead of time to adjust the flight time right or left during the mission as appropriate
On a side note, manufacturers could permit their customers to save a lot of money and obtain better flight times if they did away with the "smart" batteries and proprietary battery cases and connections. Anyone can by very good batteries with better flight times if they could use lipo's of standard design that employ EC-5 or equal connectors. You can buy those all day long for $30.00-$40.00. The fancy case thing is only about being able to charge more for a battery by eliminating end user choice in where their batteries are obtained. However, it has been demonstrated many times over that people brand new to multirotors and lipo's don't have a clue about what's involved with lipo battery care and many of them become pretty upset when they learn that doing things right requires purchasing a better charger and reading up on battery chemistries, charge and discharge practices, and general care of a lipo. Almost a Catch 22 for manufacturer's of consumer drones where you're damned if you do and damned if you don't. One thing that I think we'll find some consistency is with is advertised flight times. Whatever is advertised will be more than what we will actually obtain when we fly. We can accept that fact or become angry, but the situation isn't going to change any time soon.