to cvs or to subversion
First surprise, after migration, the size of my subversion folder is double the size of my cvs folder. With a bunch of 2Gb disks shared amoung dozens of unix persons, and regular reminders the current usage reached 100%, you will feel the pain of having each developers doublesizing its home directory…
The reason is a .svn/test-base directory containing a duplicate of your local copy.
The benefit there is that it reduces network usage, for instance when diffing with the working version.
Second surprise, not sure if it is a generic issue or related to the one above, a full checkout take ages 
.
svn and cvs command line interfaces almost have the same options, a bit like vi and vim -vi is my favorite- but the “tagging” massively differs. The is no cvs tag command in subversion, you use a different syntax.
cvs :
$ cd /home/lsc/CVS/proj1/source/pkg
$ cvs tag MYTAG helloworld.pkb helloworld.pks
now enjoy the power of subversion! [updated as I found the --parents option]
$ cd /home/lsc/SVN/proj1/source/pkg
$ svn copy --parents helloworld.pkb http://myserver.domain.com/svn/REPOS1/proj1/tags/MYTAG/proj1/source/pkg -m "my first svn tag"
$ svn copy --parents helloworld.pks http://myserver.domain.com/svn/REPOS1/proj1/tags/MYTAG/proj1/source/pkg -m "my first svn tag"
I always loved the cvs rename command
$ cvs rename pkg1.pkb pkg2.pkb
cvs [rename aborted]: Remote server does not support rename
Joke apart, in CVS I used to physically logon to the server and manually move the pkg1.pkb,v to pkg2.pkb,v
Renaming works in subversion :
$ svn move pkg1.pkb pkg2.pkb
A pkg2.pkb
D pkg1.pkb
Update: One more annoyance, you cannot checkout a single file
subversion faq