Pushing your CAM button

Anyone have preference on cam buttons for roller cams? Is one easier to install than another..such as less shimming or grinding and measuring. Or is there one you can just buy and install right out of the package. What about brands, Comp, Lunati, Mancini, Crane or any others. How about what it's made of.. nylon, steel roller ect.
As always, your knowledge and years of experience is appreciated.