Although preferences for signing (or not) are stated here thoroughly, I'll share mine and what my considerations are.
I mat a print so it has a half inch border around the printed area. Before I mat it I sign it on the bottom right. I put a label on the back (on the backing board, not on back of the print). I didn't weigh one method over another, it just seemed natural to do it this way.
In the beginning I matted right up to the border of the printed area and signed the mat. It occured to me that if the work is re-matted then the old mat with signature goes into the trash can. I concluded that signing the mat made no sense, so I stopped. My other conclusion was that signing in a border around the print made sense since the signature would be maintained no matter if the print is re-matted. I also like the look of the half inch border.
Why do I sign the print at all? Most of the work I do is photographic art. I do one piece at a time. I work it from capture, to printing to matting and framing. Many works of art are signed - it's quite natural. I don't anticipate the signature increasing the value of my work - it just indicates that it is my work. I don't confer with the customer if they want the work signed or not; it comes that way. Now, of course I don't sign all of my work - it depends on it's intended use. I've been shooting a lot of TFP with models lately. I don't sign prints that they intend to use in their portfolio. But if it is art, I sign it. Oh, when I look at the framed piece, in my personal experience it does not distract from the art.