Mint KDE is really good, but I also looked at the KDE 4.3 live cd (openSuse 11.1) at the same time. Both were installed and evaluated. The reason I decided to go with the Suse is because KDE 4.3 is so much better than 4.2.4 I cannot stand to go back anymore. Another thing I've learned is that there are other rewards to using a openSuse distro, like certain softwares that are available if you are willing to do the work. Playing with Google Chrome, for example.
Although Mint KDE is terrific, openSuse is quick with various updates and does not lag behind a "main" counterpart by a few months. This is not meant as a slam against the work done here, just a summation of my opinions. A user who is not comfortable with searching for various codecs and the horror of YAST should choose Mint instead.