I encourage you to be careful with the 39 as it is about to be replaced by the 390 or 390S.
If it limited only to the three you have mentioned, I would probably recommend the YBA. I have not heard it in quite a while but was extremely impressed when I did. The Meridian 508.24 is pretty good as well, but I was not blown away by it. I actually compared it head to head with a "cheapie" Rotel 955 (if I remember the model correctly) and the Meridian was only marginally better. I was a bit surprised. Unfotunately, I have never heard the Copland so I of course immediately kicked it off the list. :)
If it limited only to the three you have mentioned, I would probably recommend the YBA. I have not heard it in quite a while but was extremely impressed when I did. The Meridian 508.24 is pretty good as well, but I was not blown away by it. I actually compared it head to head with a "cheapie" Rotel 955 (if I remember the model correctly) and the Meridian was only marginally better. I was a bit surprised. Unfotunately, I have never heard the Copland so I of course immediately kicked it off the list. :)