Yo, I'm April, and this is my little 2.5" drone to stay below 250g and avoid RemoteID restrictions here in the USA while keeping the flight performance somewhere near that of a 4-5" as best I can. 

Firmware FC - Betaflight
Firmware ESC - BlueJay

Note: At this time I have upgraded to the HGLRC Zeus 3-8s ESC for assurance on not burning out the ESC, as I am running 6s LiHV, which would be pushing on the regular 6s-rated ESC that comes with the Speedybee F405 mini BLS Stack.

Opinions: Having flown 5" for many years now, I am now finding more fun out of these smaller 3-2.5" drones due to many reasons. Firstly, due to its smaller size, it makes it much more viable to fly around in proximity, like parks (empty, of course), where tighter gaps made it difficult to fly a 5" in proximity. Second, having this 2.5" makes it much easier to pack into a bag. For example, I have on many occasions now brought my drone in my school bag to fly in between classes, where if I had my old 5", it would have been goofy, or I would have had to carry around a separate bag.

As for performance, it of course is not exactly like a 5" with the main drawback being momentum carrying. Doing power loops around larger trees are still very possible, but you have to essentially force it with some throttle; otherwise, you will run out of momentum on the back end of the loop, where you could get too close and catch a branch. 

For flight time, I get around 3-5 minutes depending on if I bash it or fly relaxed and cinematic.