I find locking tuners unnecessary and don't like more weight or complication but they're OK and some relay on them in their setup routines, so, OK. Cheap tuners are simply not good. They get slippy and imprecise fast, and feel bad, too. Respectable names (except Kluson, IMO) are all OK. Frankly, none are really all that good until you get up to the boutique models -- it amazes me that no one is putting out a true quality unit at a really good price. So: avoid cheapies; decent mainstream brands = OK but not really great; expensive models by reputable makers are good. Great? Absolutely none that I know of. I always go with the best I can afford, but have never come away "wowed" at all. What junk, really.