I think 2 versions of a song can be good at times, but I don't usually like to do it. Mostly because I felt I was kinda burned on a 2 version song. I won't mention the song, but it was a long time ago, early in my collaboration experience. At that time, I felt that the version I was involved in didn't get as much attention as the other version, and I don't mind saying that the other version was probably better. I just felt that the attention was all on the other version, and I got kinda left out in the cold. Both versions were completed, but I felt that alot more detail was given to the other version, as far as mix, and overall sound. Most of the same parts were used for both versions, except one had my vocals and lyrics, and the other had someone else's vocals and lyrics. In the end, the other version just sounded better, because more attention was given to it. I was never able to convince the person in charge that the mix on my version was just shotty at best, where the other version ended up sounding great. I would of liked to have my version sent through the mixer with the same attention as the other, but it never happened. In a way, I kinda felt like it was waisted lyrics. It's always hard for me to let go of a set of lyrics, and in the end that is what ultimately happened.
So what I am saying is, 2 versions are great, as long as the same detail and hard work is put into both versions.
Curtis