Argumentum ad novitatem is the fallacy of asserting that something, by virtue of being new or newer than something else, is better than something else.

My Yugo is better than your Mercedes because it was just built.

KDE is better than GNOME because KDE 2.0.1 just came out.

The 2.4 Linux kernel is better than Windows 2000 because it was released several months after Windows 2000.
Argumentum ad novitatem is the opposite of argumentum ad antiquitatem.