Need feedback/input on better lighting

Hello everyone,

i’ve worked on a simple bathroom scene for some time now and i’m struggling with the lighting a bit. I rendered a WIP shot and like the dark mood with some very diffuse blue cold lights. But these lights only work (at least in my opinion) when there is not much light arround them. The “problem” now is, i showed the render to two friends and both said it was too dark. I’m seeking for a solution where i can make it brighter and still maintain the subtle, atmospheric blue light.
I used a JPG as environment Texture (Emission) a physical sun and Emission materials for the lamps.
I heared it is better to use real lamps instead of emission materials, cause they need less render time. Is that correct?
I’m very glad for any feedback. Thanks!

Ello