bgarrant, it really is a good idea to update for security releases. I’ll admit I likely have some old personal sites on archaic versions, but I wouldn’t recommend it.
On the plus side- this is a build release rather than a version release- there are no changes to the database, so it’s a matter of replacing the files. That said- we ran into a glitch with the 2.x builds- see April 7th ExpressionEngine 2 Release Temporarily Rolled Back- so you’d want to wait for that to be resolved before proceeding.
But yes- for a security fix, it’s a good idea to get current. And this one has some critical bug fixes in it as well, so there’s an added benefit.