TL;DR: the West is more than twice as wealthy as the East, nearly none of the wealthiest citizens or largest companies are based in the East, expected lifetimes in the East have just about caught up with the West, about 10% of marriages are between Easterners and Westerners (the same proportion as between citizens and immigrants), more migrants live in the West, though the East is leading in some areas such as education and the availability of childcare, and about half of all citizens report that Easterners and Westerners have more differences than similarities.
When the wall fell, an East German aunt of mine visited relatives in both West Germany and the US. She said something like "Everyone in West Germany is rich compared to us. Then you go to America and everyone is like on Dallas (a night time soap where everyone owned oil wells and stuff)."
I was in West Germany when the wall came down. They stopped requiring ID cards to enter the American military base ("kasern" iirc). This lasted a week or so and then the Gulf War started, at which point you needed you military ID plus a second photo ID to get on base.
I watched the wall come down on TV with my baby and toddler climbing all over me. I sent care packages to East German relatives for a time after it came down and it was no longer a security risk for my husband for me to admit I was related to these people.
TL;DR: the West is more than twice as wealthy as the East, nearly none of the wealthiest citizens or largest companies are based in the East, expected lifetimes in the East have just about caught up with the West, about 10% of marriages are between Easterners and Westerners (the same proportion as between citizens and immigrants), more migrants live in the West, though the East is leading in some areas such as education and the availability of childcare, and about half of all citizens report that Easterners and Westerners have more differences than similarities.