Which LED recessed ceiling spotlights should I buy?

We now need to slowly decide on recessed downlights for our concrete ceiling. The empty housings were directly embedded in the precast concrete ceiling, and the size of the spots is relatively flexible. It should be LED. What would be a good size for the hallway, kitchen, dining room, and living room? How many lumens should such recessed downlights have? Is it acceptable to go for cheap products here, or is it worth opting for branded products (if branded, which manufacturers would be recommended)?

Have a look at Brumberg.