Downlighters

[Cj24]

Hi can someone clear up the difference between 12v and 230v downlighters for me obv I knw the main difference and all about the transformers but what would make u choose one over the other, I assuming one is more energy efficent but surely everyone wud choose this option or is it the less energy efficent is brighter too

 

[spot]

Guys, this is my first post so go easy on me! I have been asked to fit four outside recessed lighting into a canopy at the front of a house. They want white fittings to blend with the upvc. I think the lights are likely to be on for long periods of time. The canopy is water tight with a pitch, so there is plenty of air in the recess. I know i'll need IP65 fittings. I'd like to fit good quality lights which are low maintenance and energy efficient. The catalogues i've looked at are starting to boggle my brain! Can anyone suggest suitable fittings please??
Ta
Spot