From what I heard German reunification was basically just West Germany consentually eating East Germany into it's system. Were there difficulties supplying and training East German soldiers with their equipment? Did East German leadership get integrated into Western high command? Was there an effort to mix in the new personnel or were they sort of just left segregated by old units? What happened to all the Warsaw Pact gear the East Germans had lying around? Were there resentments by East Germans about their new West German generals?
German army officer and historian here. Sorry for my bad english in advance.
In the beginning of the integration of NVA and Bundeswehr there was a huge problem because the german government had signed documents to limit it military power far before the 1990s. This meant that they weren‘t allowed to integrate the whole NVA into the Bundeswehr. On the other hand, many NVA soldiers didn‘t want to serve in a united german army. I mean, they were indoctrinated that west germany was the „Klassenfeind“. But to answer your question i will divide it into the different aspects.
Material The Bundeswehr either sold, used or demolished the equipment. Most was sold to other armies. Tanks, small arms and planes were favoured by many different states in that time. Other things were stored until they found another use for it (fun fact: The stored Strela-3 are now transferred to ukraine. Unfortunately many aren‘t in good condition anymore and need to be thrown away). The MIGs on the other hand were used until the 2000s by the german air force. They were well maintained and a well liked guest by sit shows and combat trainings worldwide. The NATO had the one and only chance to test their enemies equipment against their own weapon systems. This was a huge factor by that time.
Personnel Conscripts and most of the lower rank soldiers were thrown out of the army when they morphed into each other. Only officers up until colonel and sergeants had the chance to become regular Bundeswehr soldiers. They had roughly a year after the integration to apply to a position within the Bundeswehr. If they didn‘t want to, their time as a soldier ended. There were more applies than positions, so only the best and political clean soldiers were allowed to serve into the Bundeswehr. Especially technical Sergeants had good chances to become a „Berufssoldat“ (lifetime soldier). They needed their know how to maintain the MIGs for example. On the other hand, many NVA soldiers who joined the Bundeswehr were called „Wendehälse“ (a person who is like a flag in the wind). Even in their own families. The propaganda was still strong in the heads of the east german people. But that is a point, that became less and less a problem with time going on. Today there are still former NVA soldiers within the Bundeswehr and they are perfectly integrated and well liked. In fact, they told me first handed that after the integration the were helped by nearly every Bundeswehr soldier with the daily tasks, for example how they wear the uniform correct or with a different military etiquette.
In conclusion, todays Bundeswehr says, that the integration of west and east germany were in no point better than in the military. It was well organized without bigger problems in the long run. I hope i could express what i wanted to and if you have further questions please ask me. I will do my best to answer these.