And lets not forget there are plenty of illegal halogens out there as well such as Phillips Crystal and Diamond Vision, and basically everything else that is not marked as road legal. Where you have a separate High Beam globe, stick whatever you like in there as it's a dedicated driving/spot light, but for the sake of other motorists, and overall road-worthiness, one should stick to genuine approved ADR/ECE compliant Low Beam bulbs.
Regarding HID and LED retro-fits it's pretty cut and dried in that it's illegal if the lamp assembly is not self-levelling, and self cleaning for HID. You can be pretty sure that a factory halogen lamp assembly is not self-levelling!
I researched all this before putting Cool Blue Intense into my Low Beam. From what I learned, Phillips White Vision is the best of the legal halogen upgrades regarding all round performance and longevity, but you pay extra for it. The Cool Blue Intense has slightly more blue in the colour and therefore not as effective in the rain (still satisfactory just not as good as White Vision), but costs less.