With the advent of Subversion 1.4, the working copy meta data changed, which means you can't mix 1.4 clients with earlier clients. Not a huge deal, in general, but I ran into it because I much prefer Subclipse 1.2 to 1.0, and 1.2 uses the Subversion 1.4 working copy structure, but CentOS packages a Subversion 1.3 client (and can't upgrade because of APR conflicts).
But I learned that SVNKit (formerly JavaSVN, and what Subclipse uses under the hood), ships with a command-line client that behaves like the official Subversion one. I figured I'd give it a whirl, since I occasionally need to do SVN stuff from the command line, and it works like a charm. It even seems faster than the real one, though that might be attributable to the performance improvements in the 1.4 working copy stuff, not the client itself. If you're looking for a 1.4 command-line client and the official one won't work (because you have conflicts, can't install software, etc.), I highly recommend this one.
