i assume u compare same wattages, lets say 18W vs 18W.. same temperature, either 3000k, 4300k or 6000k.. warmer color might giving u cozy and comfortable at home..

surface is used for no plaster ceiling while downlight need plaster so you would see flat profile with ceiling.. functional wise, both serve same purpose.. unless you compared with eyeball..

in my opinion, if you have plaster ceiling, you could have 3 types of light.. eyeball, downlight and cove light.. all three could serve different purpose..

standard one in market as per what i knew, 18W 6 inch size should be normal one.. dont install too much or else might be too bright.. take note about fan position & shadows angle..

surface light will trap a lot of dust & insect after sometime.. and you will see the light there.. some concrete ceiling might have crack hairline after some time and looks ugly.. so people usually do plaster ceiling, can hide all wiring, add additional light point, AC point, fan point or whatever in plaster ceiling.. looks neat..

depend on your house renovation theme.. some like to see the piping running here & there.. some dont like.. without plaster ceiling, basically you can use only the lighting point/fan point as per provided by developer.. if you have palster ceiling, you can change the location easily..

how come installed surface mounted light on plaster ceiling.. quite a waste in my opinion. ya.. surface mounted light will have screw & the hole after that.. usually ppl use downlight 4inch/5inch with spring and hide all wirings inside plaster ceiling.. so it looks like light are integrated with plaster ceiling.. showing flat surface..

maybe ur surface mounted light are those expensive & smart one.. nvm.. future if want change to downlight that time, can cover plaster hole again and change type of light easily..

in normal case, tend to use aluminium casing to put LED strip.. yes, driver is required.. can be hide inside plaster ceiling at nearby downlight for future replacement on driver..

need to calculate the length of LED strip that u required on each.. wiring works need to done at earlier phase of renovation before plaster ceiling works..