I have Spy and Smith. I like the Spy Persimmon lens best overall but it is not really great of totally flat low light days. My wife's cousin 'borrowed' the Spys and they have not come back yet - but she rated them as well.
I do not have Prodigy but Phenoms as they fit my face/ helmet better. The Phenom is great, good lens, doesn't fog very often and clears quickly if it does. Vents seem to make a difference on hotter days.
Phenom Turbo is excellent for cold foggy or snowy days, I get pretty hot and they stop the fogging that I sometimes used to get during this type of weather, especially when hiking during snow fall.
I have the Polarised Rose Copper Lens in the Phenom which is great for everything from low light to bright sunny days. This is one of the best eyewear lens tints I have ever used - the clarity is awesome.
Sensor Mirror lens in the Phenom Turbos - great for low flat light through to moderately bright. A pretty good lens but not as good as persimmon (Spy).
Platinum Mirror - The turbo version of the Rose Copper without the polarisation. Awesome lens but to be honest I do not use it very often because when it is bright enough to use it it is normally warm enough that I do not get fogging so I use the normal Phenoms with the Polar Rose Copper lens.
RC36 - like the persimmon good for all round conditions, great clarity and contrast. Not as good as the Polarised Rose Copper at the low light end of the use spectrum (but half the price).
Yellow lens - the best for really really flat light where there is no chance of sunlight ie seriously overcast, heavy fog/ low cloud or heavy snow. Great snow contrast in these conditions. Used for racing when they are almost at the 'should we call the race?' point.
I cannot be bothered with the scratches and finger prints of 'quick' lens changes and quite often ski with both pairs (one in pocket). I believe that in the long term having two pairs of goggles saves on damage to lens through changing them.
A caution with Smith lens (printed on the instructions) do not wipe the inside of the lens when it is damp - it damages the anti-fog coating. One can blot it with a tissue/ napkin or a good lens cloth (spanky works well) to remove post crash snow.
Try them on with your beanie/ helmet and get the model that best suits your face shape (ie size/ curve/ nose etc). If you can get the sales then get two as it makes sense in the long run.