I've just received an assignment to upgrade an old Delphi 3 project that I wrote in 1999 to a newer version and add features (I previously discussed this in related questions here and here). I was assuming that the appropriate route would be to first upgrade my development environment to Delphi 2010 and then port the application.
I'm now considering whether to upgrade the application to my existing copy of Delphi 2007 instead in order to avoid the Unicode complications. The application runs at a single company in the United States and is tightly bound to requirements of a single state, so it would not benefit from Unicode support.
My question is: would the additional hassle of dealing with Unicode issues outweigh the benefit of using the most recent version of Delphi? You may assume that I have no experience with Unicode.
They have done such a good job implementing Unicode in Delphi 2009 that most programs that do not do tricks with characters and bytes convert over with no problem.
The caveat is as long as you are not using any 3rd party packages. If you are, you should upgrade those. If they don't have upgrades and you don't have their source code, then you might be better off not going to Delphi 2010.
But I would make the jump if at all possible. I did and I'm glad I did.