A few days ago I bought some old jazz and swing though the iTunes stores. Without having anything to judge the different recordings by other than the description and a 30 second sample -- which I believe iTunes chooses -- when I encountered many different albums and recordings of Duke Ellington doing "Take the 'A' Train," I chose the longest version. I figure with jazz the longer the version the more improvisation and solos.
In this case there was one problem. The version I bought, which comes from Duke Ellington At the Hollywood Empire is apparently from a radio show, and has three or four interruptions where a host comes on and tells us something about the performers. If I'd known about that, I probably would have gotten another version.
Aside: Is it just me or do all of the big band radio hosts from the 1940's sound like the same guy.