I have Calmini shackles on mine. The blue powdercoat peels off after a year in the midwestern salt, but it's ok with me.

In all honesty, they all work the same. It's the same piece of metal performing the same function. There's not gonna be much difference bwtween them, however the ones from SLR (if I'm not mistaken arre slightly shorter and will give you a little less lift, maybe by 1/2 inch or so.

EDIT: If you look around this section (on the bottom of the page select ' list topics from beginning') you'll find everything you need about a PML and more, but don't worry about asking if you need more info.