There are many different makes and brands of machine heads available to the guitar maker. Unfortunately, a large majority have backlash (when you tune the string up or down and you have to turn the tuning know half a turn before the gears engage) and a limited life-span.
I use Waverly and the Sloane machine heads as they are semi-handmade and are available with tuning knobs of snakewood to match my Brazilian Rosewood back and sides. I also use Gotoh machine heads for the musician who requires a closed back machine head. The Gotohs are also incredibly smooth. All of these machine heads are able to withstand the rigours of the professional musician’s constant tuning needs.