Tom Mornini (tmornini@infomania.com) is a long time Perl programmer and version control fanatic.
I do version control consulting for a large commercial vendor but prefer open source solutions for my own code.
Subversion is fantastic, but SVK takes it up to the next level.
I think SVK, rather than being a competitor to Subversion, is actually a testament to the wonderful foundation that Subversion provides.
Best SVK feature: History sensitive merging!
Second Best SVK feature: No .svn directories in working copies!