is there firmware support from Navifly?
Does it release updates of fw and mcu and where is possible to find it?
Do you think it is a reliable radio?
Reliabilty is not the strongest selling point of any of those Chinese units.
I guess they are more or less basically the same for any manufacturer over the several resellers: FYT as manufacturer in this case.
I also guess that the "mini"-assembly the resellers do, like TN/IPS/QLED screens can differ, but not so much.
The greatest difference could be in support: service desk, firmwares, broken parts, etc.
And I really have no clue there about Navifly.
As I don't have a Navifly I did not look at all for their firmware. And for that matter: Neither for firmware from Kingsbeat, Navifly, Zhan, etc.
And when it comes to firmware: All FYT compatibles on the same CPU, with/without DSP, in the same aspect ratio* can, with some tweaks, run each others firmware.
Now with the new models and new firmwares having protection in the apks, coupled to the MCU it gets more difficult.
*: not resolution, but aspect ratio: FYTs screen layouts in the apks are terribly old-fashioned and fixed: 1024x600 / 1280x730 =>16:9; Other layouts like 1280x480 or "Tesla style" really require a different firmware. FYT currently can only accomodate the several resolutions if the screen has the same aspect ratio. That is also one of the reasons the FYT apps themselves do not support split-screen. A feature they so much like to advertize, but doesn't work for their own apps. A few new developed apps do support this finally.