my luthier replaced the standard tuning machines in my G&L L2k5 in order to shed some weight - these are almost 50% lighter than the originals! a drop-in replacement, save for the screw holes from the originals, which were filled in.
pro:
they seem to be very well made, precisely machined and built to last. very smooth action and do what they are supposed to do. visually almost no difference when observed from the front - not that it matters to me personally. absolutely worth the price, would buy again. Schallers bridges are also top notch.
con: none.