I had two German uncles, one my mother's brother, the second her brother-in-law. Both were captured in Russia in 1943. My blood uncle (who was a Panzer support sergeant) was fortunate in as far as he was released in 1951, suffering extreme ill-health. I think such releases were rare. My second uncle, Max (an infantry sergeant), was kept in Siberia driving timber lorries until 1955. His story was that by then people who could drive these unwieldy vehicles on terrible roads were invaluable to the Russians and were kept hold of for as long as possible. He was able to live reasonably freely as escape was impossible, and was adequately fed and housed at least from the early 50s. They were both in their own way lucky, for, as has been well rehearsed above, the great majority of German PoWs in Russia died in captivity.
Not sure if the Pathé film of Germans returning from the USSR has been posted in here before. I found it interesting.