I'm certain sites like Digital Foundry will do extensive framerate and visual quality
testing and
comparison (they really are the best in the business at it — I will link to their hard work when they inevitably unveil it), so I'll constrain my impressions to two different perspectives — mine as a lifetime
hardcore gamer, and that of my casual gaming wife who has frequently said «I can't see any difference» in the past.
He understands that some of the more
hardcore users in the community have been
testing and pointing out
comparisons between 4 GB and 6 GB phone models.