My OnGuard mini (purchased summer of '08) is a PITA to use. So is my cheap Kyptonite. Both have to be fiddled with to use.

I bought the OnGuard thinking it would be lighter, but it's not, just smaller. I suppose it's harder to pry apart, but it is also harder to get around a pipe. Getting the crossbar on the shackle can be a problem, and then when you're past that, the lock mechanism can be tricky.