I recently bought a set of the (Schaller) Fender locking tuners to help with stabilising the tuning on an old 1990 Japanese Squire Strat, which over the years has gone on to become my favourite guitar. The tuners fitted extremely easily (the guitar fortunately had the pre drilled holes in exactly the right spot) are smooth to use and make string changing far easier ... quiet why fender don't fit these as standards on all their guitars is beyond me after using them for a couple of weeks now? For the ease of changing strings alone they are worth fitting to any guitar, with or without a tremolo. I will now fit them on my USA Strat too ... I just can't fault them. I thought they were very reasonably priced too. Although not as good a full on bolted down Floyd Rose type system, the tuning is immeasurably better on the guitar with the locking tuners than it was before I fitted them.
I'm not a sound aficionado but I mounted these on my custom Squier and they do a great job staying in tune. IMHO these are premium tuners. I've seen these on premium guitars and they look great on any guitar!
Cons: You have to drill holes yourself if you mount them on a Squier guitar made in Indonesia.