Visible Transmission (VT)
VT is the transfer of light of visible wavelength. VT is usually expressed for the whole window, but the important value is the one for the glass.
A high value of visible transmission brings in daylight and reduces the need for artificial light in your home or office.
The visible transmission should be evaluated for each project. Depending on climate area, elevation and available natural (e.g. trees) and artificial (e.g. blinds & curtains) shading options each project has its own requirement.
Increasing the visible transmission in cold climates can be beneficial. It can reduce the need to artificial lighting. Keep in mind that thermal performance might have an impact on your choice as well.
In hot climates improved shading might create a higher comfort. It can be beneficial to use the shaded glass option to reduce light transmission and heat gain to lower cooling costs and unwanted bright indoor environment. The available glass options can also help to reduce the impact of fading (discolouration of curtains, carpet etc.)
Glass options and sizes of windows and doors influence the performance.
Glass coatings are available in different colours. Grey and green are the typical choices.
Keep in mind that elevation, climate and landscape you live in, as well as the looks, should influence your decision.
There is no general rule. It is important to find the right solution to match your requirements.