Hi Guys,
I use locking tuners on all my guitars,
I generally use Sperzels, which are great, I use Schallers on my H series guitars, and have used the Planet Waves.
I was a bit unsure of the build quality of the Planet Waves, but they have proven themselves to be good performers, they also have this neat feature that cuts the excess string off as you wind them on.
Sperzels also have a nice feature, in that you can unscrew the winder off the machine head and reverse it, so they can be either left or right. great if you are building a guitar with 2 + 4 or for a seven stringer
Sperzels do have a lower gear ratio than the schallers, but it is not too much of a difference
I have over 50 guitars out there and lockers are on all of them.
Pete