New supplies and chemistry involved in the most current generations of the lenses have created substantial development in addressing the 2 fundamental requirements for choice :
Older generations (and a few current generations) retain a yellow or slightly jaundiced hue even if not uncovered to extremely violet gentle (indoors for example). The newest technology Transitions are widely regarded to be the best accessible and almost completely obvious inside the absence of ultra violet.
Most more recent photochromatic lenses produce a fast changeover from mild to darkish as they are uncovered to ultra violet - the real test and the differentiation is the rate at which they regress in the darkest tint to distinct. Once again Transitions lenses are extensively regarded as best in class in this regard.
Transitions lenses are a widely held trademark to get a distinct (most recent) technology of materials and technologies which can be combined and offered beneath the "Transitions" brand name. Other (but related) names will not be exactly the same, and therefore are usually regarded to be not as excellent, as they're from older era photochromatic technologies.
Ultimately - never expect your photochromatic lenses (irrespective of which brand or technologies) to produce considerably of the difference whilst driving, as the windscreen of the automobile is made to absorb many of the UV just before it enters the cabin - therefore the lenses within your eyeglasses have absolutely nothing to respond with. If you want or would like tinted lenses whilst driving, you happen to be far better off acquiring two pairs in the same body with prescription obvious and prescription tinted lenses.