I haven't used BikeLink, but I've been considering it lately, since there's a station near a movie theatre I frequent, and I think it would be nice to have a more secure place to lock my bike for upwards of three hours, often at night, than on the street.
I spent some time last weekend talking to people who used the station I would use (I just skulked outside and talked to people as they went in). They all found it convenient and most of them felt it was safe enough to leave accessories on their bikes, unlocked, which is a major plus. Of course, no place is that secure, but I could see leaving lights on or something like that.