Which device to use depends on your use case and your budget.
All our Android TV boxes are perfectly suitable for 4K, Kodi, IPTV and any streaming apps.
I have created a compare products page for you so you could check differences:
Use this link - Compare products - DroiX
A95X Max is the best option if you are going to use 2.5 HDD Drive DroiX X3 is the best budget Android box which also comes with G10 Airmouse Beelink GT King is the top range Android TV Box which comes with powerful Amlogic S922X SoC which is popular not only for streaming, but also for emulating various retro gaming consoles, like PSP, PlayStation 1, Dreamcast and others ( you would need to install RetroArch and use ROMs)
So which one go is up to you. Let us know if you have any more questions.