I would get the meizu pro 6 plus as it cheaper now and will be cheaper when pro 7 would be announced. Mx6 is great but it is getting old and you can get new phones with new features.
The m5 family of meizu is not recommended as you can get better phones with that price.
Xiaomi has their redmi note 4 which is good and mi 5 and mi max 2.
Other than those companies i cant recommend other phones as one plus 3t is still above 400 and other phones i never tested or only saw pictures.
And samsung lg and apple just ask for a lot more than chinese manfucturer for less than chinese so it wont be smart to buy them if you wont spend above 400.