I like explicit closes. I like explicit lots of things that Perl auto-does if given a chance.
On the maintainability front, an explicit close() tells the maintainer that the author "meant to do that" and "here". No explicit close leaves questions. Did they mean to let it close automagically, or did they leave out the close where they really wanted it, etc.
I rarely have the luxury of working with expert Perl programmers. The more that's done explicitly and clearly, the better for everyone involved.